Electrical components for physiological monitoring device

ABSTRACT

The present disclosure relates to a device configured to be adhered to the surface of a mammal for recording physiological signals. The device may include a housing enclosing a circuit board and a flexible wing extending from the housing. The device may include an electrode coupled to the flexible wing and an electrical trace for transmitting an electrical signal between the electrode and the circuit board. The electrical trace may have an insulator with a conductive material and resistors printed on the surface of the insulator. The trace layer may include conductive vias for transmitting the signal from a bottom of the trace layer to a top of the trace layer. The housing may include a battery having a battery terminal connector configured to provide electrical access to both terminals on a single side of the battery. The housing may include a floating trigger button.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. patent application Ser. No.17/396,491, filed on Aug. 6, 2021, which claims priority to U.S.Provisional App. No. 63/062,314, filed on Aug. 6, 2020, which is herebyincorporated by reference in its entirety.

BACKGROUND

For purposes of this disclosure, certain aspects, advantages, and novelfeatures of various embodiments are described herein. It is to beunderstood that not necessarily all such advantages may be achieved inaccordance with any particular embodiment. Thus, various embodiments maybe or carried out in a manner that achieves one advantage or group ofadvantages as taught herein without necessarily achieving otheradvantages as may be taught or suggested herein.

FIELD OF THE INVENTION

Disclosed herein are materials, devices, methods, and systems formonitoring physiological signals. For example, such physiologicalsignals may include heart signals, such as an electrocardiogram signal.

DESCRIPTION OF THE RELATED ART

Abnormal heart rhythms, or arrhythmias, may cause various types ofsymptoms, such as loss of-consciousness, palpitations, dizziness, oreven death. An arrhythmia that causes such symptoms is often anindicator of significant underlying heart disease. It is important toidentify when such symptoms are due to an abnormal heart rhythm, sincetreatment with various procedures, such as pacemaker implantation orpercutaneous catheter ablation, can successfully ameliorate theseproblems and prevent significant symptoms and death. For example,monitors, such as Holter monitors and similar devices, are currently inuse to monitor heart rhythms.

BRIEF SUMMARY OF EMBODIMENTS

Embodiments described herein are directed to a physiological monitoringdevice that may be worn continuously and comfortably by a human oranimal subject for at least one week or more and more typically two tothree weeks or more. In one embodiment, the device is specificallydesigned to sense and record cardiac rhythm (for example,electrocardiogram, ECG) data, although in various alternativeembodiments one or more additional physiological parameters may besensed and recorded. Such physiological monitoring devices may include anumber of features to facilitate and/or enhance the patient experienceand to make diagnosis of cardiac arrhythmias more accurate and timely.

In some embodiments, an electronic device for monitoring physiologicalsignals in a mammal comprises: at least two flexible wings extendinglaterally from a housing, wherein the flexible wings comprise a firstset of materials which enable the wings to conform to a surface of themammal and the housing comprises a second set of materials; a printedcircuit board assembly housed within the housing, wherein the housing isconfigured to prevent deformation of the printed circuit board inresponse to movement of the mammal; at least two electrodes embeddedwithin the flexible wings, the electrodes configured to provideconformal contact with the surface of the mammal and to detect thephysiological signals of the mammal; at least two electrode tracesembedded within the wings and mechanically decoupled from the housing,the electrode traces configured to provide conformal contact with thesurface of the mammal and transmit electrical signals from theelectrodes to the printed circuit board assembly; and, at least onehinge portion connecting the wings to the housing, the hinge portionsconfigured to flex freely at the area where it is joined to the housing.

In certain embodiments, each wing may comprise an adhesive. Inembodiments, the electrodes can be in the same plane as the adhesive. Incertain embodiments, each wing comprises at least one rim, wherein therim is thinner than an adjacent portion of each wing. The housing mayfurther comprise dimples or grooves configured to allow for airflowbetween the housing and the surface of the mammal. In certainembodiments, the rim is configured to prevent the release of a portionof the wing from the surface of the mammal. In some embodiments, anelectronic device for monitoring physiological systems may comprise ameasuring instrument configured to detect motion signals in at least oneaxis. This measuring instrument may be an accelerometer that can beconfigured to detect motion signals in three axes.

In embodiments, the motion signals can be collected in time with thephysiological signals. In certain embodiments, a motion artifact isidentified when the physiological signals and the motion signals match.Further embodiments may call for an event trigger coupled to the printedcircuit board assembly. In some embodiments, the event trigger input issupported by the housing or floating on a shock absorber such as aspring or foam so as to prevent mechanical stress on the printed circuitboard when the trigger is activated which, in turn, can reduce a sourceof artifact in the recorded signal.

In some embodiments, the event trigger may be concave or convex andlarger than a human finger such that the event trigger is easilylocated. In some embodiments the event trigger may be convex within theconcave area. In certain embodiments, the electrode traces areconfigured to minimize signal distortion during movement of the mammal.In particular embodiments, gaskets may be used as a means for sealableattachment to the housing.

In certain embodiments, a method for monitoring physiological signals ina mammal may comprise: attaching an electronic device to the mammal,wherein the device comprises: at least two electrodes configured todetect physiological signals from the mammal, at least one measuringinstrument configured to detect secondary signals, and at least twoelectrode traces connected to the electrodes and a housing; and,comparing the physiological signals to the secondary signals to identifyan artifact.

In certain embodiments, identification of artifacts comprises acomparison between the frequency spectrum of the physiological signalsand the frequency spectrum of the secondary signals. In embodiments, thesecondary signals comprise motion signals that may be used to derive theactivity and position of the mammal. In certain embodiments, thesecondary signals are collected in three axes. In some embodiments, atertiary signal may also be collected. In certain embodiments, thesecondary signals comprise information about the connection between theelectronic device and the mammal. In some embodiments, the secondarysignals may be used to detect when the mammal is sleeping.

In some embodiments, a method of removing and replacing portions of amodular physiological monitoring device may comprise: applying thedevice described above to a mammal for a period of time greater than 7days and collecting physiological data; using the device to detect afirst set of physiological signals; removing the device from the surfaceof the mammal; removing a first component from the device; and,incorporating the first component into a second physiological monitoringdevice, the second physiological monitoring device configured to detecta second set of physiological signals.

In some embodiments, the first component is electrically connected toother device components without the use of a permanent connection. Insome embodiments, the device may further comprise spring connections. Incertain embodiments, the first component may be preserved for a seconduse by a housing to prevent damage. In particular embodiments, the firstcomponent is secured within a device by a mechanism that is capable ofre-securing a second component once the first component is removed.

Certain embodiments may concern a system for inferring cardiac rhythminformation from time-series data of heartbeat intervals, as obtainedfrom either consumer wearable or medical device products. A furtheraspect includes improvements to the system to enable cardiac rhythminformation to be inferred in a more robust and/or timely manner throughthe use of additional sources of data. This additional data may includesummary statistics or specific signal features derived from an ECG, useractivity time series data derived from an accelerometer, informationrelated to user state, or information related to the day/time of therecording.

In certain embodiments, a system for selective transmission ofelectrocardiographic signal data from a wearable medical sensor, whereQRS refers to the three fiducial points of an ECG recording at the timeof ventricle depolarization, may comprise:

a wearable medical sensor incorporating a QRS detector that produces areal-time estimate of each R peak location in the ECG;

transmission of an R-R interval time series together with an onset timestamp from the sensor to a smartphone or Internet-connected gatewaydevice, according to a predefined schedule;

transmission of the R-R interval time series and the onset time stampfrom the smartphone or internet-connected gateway device to a server;

server-side algorithmic inference of the most probable rhythms and theironset/offset times from the R-R interval time series data;

filtering the list of inferred heart rhythms according to specificfilter criteria, such that only inferred rhythms matching the givencriteria are retained after filtering;

transmission of the onset/offset time for each rhythm remaining afterfiltering, from the server to the smartphone or internet-connectedgateway device;

transmission of the onset/offset time for each rhythm remaining afterfiltering, from the smartphone or internet-connected gateway device tothe wearable sensor;

transmission of the section of recorded ECG corresponding to eachonset-offset time pair from the sensor to the smartphone orinternet-connected gateway device;

transmission of the section of recorded ECG corresponding to eachonset-offset time pair from the smartphone or internet-connected gatewaydevice to the server;

The rhythm filter criteria may be specified by a physician or othermedical professional prior to the use of the wearable sensor by apatient. In some embodiments, the rhythm filter criteria are dynamic andcan be updated during the use of the system according to predefinedrules. In some embodiments, these predefined rules may describe anadjustment to the filter criteria based on previous findings during useof the system. In some embodiments, the onset and offset time for eachinferred rhythm may be adjusted such that the resulting duration foreach rhythm is less than a given maximum permissible duration. Computedconfidence measures may be an input to the rhythm filter criteria. Insome embodiments, the system comprises inferring cardiac rhythminformation from R-R interval time series data. In certain embodiments,the cardiac rhythm inference system is implemented as a cloud serviceaccessible via an API.

In certain embodiments, the cardiac rhythm inference system is providedthrough a software library that can be incorporated into a standaloneapplication. The R-R interval values may be estimated from aphotoplethysmography signal.

In certain embodiments of a method for inferring cardiac rhythminformation, the cardiac rhythm inference system computes a confidencescore for each type of cardiac rhythm, the method comprising:

computing the frequency and duration of each cardiac rhythm typeinferred from the collection of R-R interval time series data for thegiven user;

estimating a confidence statistic for each rhythm type based on theinferred frequency and duration of the rhythm across the collection ofR-R interval time series for the given user;

evaluating if the confidence statistic for each inferred rhythm exceedsa pre-determined threshold value;

providing rhythm information back to the calling software only for thoseinferred rhythms for which the confidence statistic exceeds thethreshold value;

In certain embodiments, the cardiac rhythm inference system acceptsadditional sources of data, comprising one or more of:

user activity time series data measured by an accelerometer;

information on the specific day and time of each R-R interval timeseries recording;

information on user age, gender, clinical indication for monitoring,pre-existing medical conditions, medication information, and medicalhistory;

ECG signal features and summary statistics, such as the mean, median,standard deviation or sum of the ECG signal sample values within a giventime period;

a confidence rating provided by the measurement device to indicate thequality of heartbeat estimation, for example, for each beat or forsequential time periods; and

intra-beat interval measurements.

In embodiments, a system for monitoring cardiac signal data, comprises:

a wearable medical sensor, the wearable medical sensor configured todetect cardiac signals from a mammal and estimate the R-peak locationwithin the cardiac signal;

wherein the wearable medical sensor is configured to transmit an R-Rinterval time series and a time stamp to an intermediary device, theintermediary device configured to further transmit the R-R interval timeseries and time stamp to a server;

wherein the server is configured to infer the most probable rhythms andtheir onset/offset times from the R-R interval time series and timestamp, the server configured to filter the most probable rhythmsaccording to a first criteria into a filtered data set;

wherein the server is configured to transmit the filtered data set backto the wearable sensor via the intermediary device; and

wherein the sensor transmits the full resolution cardiac signal to theserver for a time period surrounding each of the filtered events.

In certain embodiments, a system for monitoring cardiac signal datacomprises:

a server configured to communicate with a wearable sensor, the wearablesensor configured to detect cardiac signals from a mammal and estimatethe R peak location within the cardiac signal;

wherein the wearable sensor is configured to transmit an R-R intervaltime series and a time stamp to the server;

wherein the server is configured to infer the most probable rhythms andtheir onset/offset times from the R-R interval time series and timestamp, the server configured to filter the most probable rhythmsaccording to a first criteria into a filtered data set; and

wherein the server is configured to transmit a summary of the filtereddata.

In particular embodiments, a server for monitoring cardiac signal data,comprises:

a portal configured to communicate with a wearable sensor, the wearablesensor configured to detect cardiac signals from a mammal and estimatethe R peak location within the cardiac signal, wherein the wearablesensor is configured to transmit an R-R interval time series and a timestamp to an intermediary device, the intermediary device configured tofurther transmit the R-R interval time series and time stamp to aserver;

a processor configured to infer the most probable rhythms and theironset/offset times from the R-R interval time series and time stamp, theprocessor configured to filter the most probable rhythms according to afirst criteria into a filtered data set; and

wherein the server is configured to transmit a summary of the filtereddata set.

In embodiments, a non-transitory storage medium havingcomputer-executable instructions stored thereon, the computer-executableinstructions readable by a computing system comprising one or morecomputing devices, wherein the computer-executable instructions areexecutable on the computing system in order to cause the computingsystem to perform operations comprises: receiving, by a computing systemthrough a communication link, physiological sensor data generated by apatient monitoring device, the physiological sensor data associated witha first patient; analyzing, by the computing system, the physiologicalsensor data to determine whether one or more points in the physiologicaldata that are likely indicative of one or more predetermined set ofconditions; and after determining that at least one of the one or morepoints in the physiological data is likely indicative of at least one ofthe one or more predetermined set of conditions, generating, by thecomputing system, an electronic data package for transmission to thepatient monitoring device, the electronic data package includinglocation data regarding the at least one of the one or more points inthe physiological sensor data that are likely indicative of the at leastone of the one or more predetermined set of conditions.

In certain embodiments, the physiological sensor data may comprise asampling of interval data measured from the recorded signal data, thesampling of interval data of a data size less than the recorded signaldata.

In particular embodiments, a system for monitoring physiological signalsin a mammal may comprise: a wearable adhesive monitor configured todetect and record cardiac rhythm data from a mammal, the wearableadhesive monitor configured to extract a feature from the cardiac rhythmdata; and wherein the wearable adhesive monitor is configured totransmit the feature to a processing device, the processing deviceconfigured to analyze the feature, identify locations of interest, andtransmit the locations of interest back to the wearable adhesivemonitor.

In certain embodiments, a system for assessing physiological sensor datafrom a patient monitoring device comprises: a computer processor andnon-transitory computer-readable media combined with the computerprocessor configured to provide a program that includes a set ofinstructions stored on a first server, the set of instructions beingexecutable by the computer processor, and further configured to executea sensor data inference module of the program; the sensor data inferencemodule of the program storing instructions to: receive physiologicalsensor data generated by a patient monitoring device, the physiologicalsensor data associated with a first patient; analyze the physiologicalsensor data to determine whether one or more points in the physiologicaldata that are likely indicative of one or more predetermined set ofconditions; and after determining that at least one of the one or morepoints in the physiological data is likely indicative of at least one ofthe one or more predetermined set of conditions, generating anelectronic data package for transmission to the patient monitoringdevice, the electronic data package including location data regardingthe at least one of the one or more points in the physiological sensordata that are likely indicative of the at least one of the one or morepredetermined set of conditions.

In certain embodiments, a computerized method may comprise: accessingcomputer-executable instructions from at least one computer-readablestorage medium; and executing the computer-executable instructions,thereby causing computer hardware comprising at least one computerprocessor to perform operations comprising: receiving, by a servercomputer through a communication link, physiological sensor datagenerated by a patient monitoring device, the physiological sensor dataassociated with a first patient; analyzing, by the server computer, thephysiological sensor data to determine whether one or more points in thephysiological data that are likely indicative of one or morepredetermined set of conditions; and after determining that at least oneof the one or more points in the physiological data is likely indicativeof at least one of the one or more predetermined set of conditions,generating, by the server computer, an electronic data package fortransmission to the patient monitoring device, the electronic datapackage including location data regarding the at least one of the one ormore points in the physiological sensor data that are likely indicativeof the at least one of the one or more predetermined set of conditions.

These and other aspects and embodiments of the invention are describedin greater detail below, with reference to the drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are perspective and exploded profile views,respectively, of a physiological monitoring device, according to oneembodiment.

FIGS. 2A and 2B are top perspective and bottom perspective views,respectively, of a printed circuit board assembly of the physiologicalmonitoring device, according to one embodiment.

FIGS. 3A, 3B, 3C, 3D, and 3E are perspective and exploded views of aflexible body and gasket of the physiological monitoring device,according to one embodiment.

FIG. 4 is an exploded view of a housing of the physiological monitoringdevice; according to one embodiment.

FIGS. 5A and 5B provide a perspective view of a battery holder of thephysiological monitoring device, according to one embodiment.

FIGS. 6A and 6B are cross sectional views of the physiologicalmonitoring device, according to one embodiment.

FIG. 7 is an exploded view of the physiological monitoring deviceincluding a number of optional items, according to one embodiment.

FIGS. 8A and 8B are perspective views of two people wearing thephysiological monitoring device, illustrating how the device bends toconform to body movement and position, according to one embodiment.

FIGS. 9A, 9B, 9C, 9D, 9E, and 9F illustrate various steps for applyingthe physiological monitor to a patient's body, according to oneembodiment.

FIGS. 10A-10C schematically illustrate alternative examples of a tracelayer. FIG. 10A illustrates a first example of a trace layer and FIG.10B depicts a close-up of the inset A of FIG. 10A. FIG. 10C illustratesanother example of a trace layer.

FIGS. 11A-11I schematically depict examples of a battery terminalconnector. FIG. 11A depicts an inner surface of a battery terminalconnector configured to contact the battery terminals and FIG. 11Bdepicts an outer surface of the battery terminal connector opposite thesurface depicted in FIG. 11A. FIG. 11C depicts an inner surface ofanother example of a battery terminal connector configured to contactthe battery terminals and FIG. 11D depicts an outer surface of thebattery terminal connector opposite the surface depicted in FIG. 11C.FIG. 11E illustrates a side view of a battery to which a batteryterminal connector has been coupled. FIGS. 11F and 11G depict an innersurface of another example of a battery terminal connector configured tocontact the battery terminals. FIGS. 11H and 11I depict an outer surfaceof the battery terminal connector opposite the surface depicted in FIG.11C.

FIGS. 12A-12G illustrate multi-perspective views of another example ofan upper housing. FIG. 12A depicts a partially exploded view of theupper housing. FIG. 12B shows a perspective view of a flexible upperframe. FIG. 12C shows a side view of the flexible upper frame. FIG. 12Dshows a top view of the flexible upper frame. FIG. 12E depicts aperspective view of an inner surface of the upper housing. FIG. 12Fdepicts a side view of the upper and lower housing. FIG. 12G depicts aside view of a ridge configured for sealing the top and bottom portionsof the housing.

FIGS. 13A-13B illustrate multi-perspective views of another example of alower housing. FIG. 13A depicts a perspective view of the lower housingand FIG. 13B depicts a side view of the lower housing.

FIGS. 14A-14B illustrate orthogonal side views of an example of a wavespring.

FIGS. 15A-15I illustrate multiple views of another example of aphysiological monitoring device. FIG. 15A depicts a perspective view ofthe physiological monitoring device. FIG. 15B depicts an exploded viewof the physiological monitoring device. FIG. 15C depicts a side view ofthe housing in which the upper housing has been removed. FIG. 15Ddepicts a side view of the housing as shown in FIG. 15C with flexibleupper frame additionally being removed. FIG. 15E depicts a side view ofthe housing as shown in FIG. 15D with the lower housing additionallybeing removed. FIG. 15F depicts a side view of the housing as shown inFIG. 15E with the battery and spring additionally being removed. FIG.15G depicts a sectional view of the housing as shown in FIG. 15F withthe section taken between the circuit board 120 and the spring contactspacer 632. FIG. 15H depicts a sectional view of the housing as shown inFIG. 15G with the spring contact spacer additionally being removed. FIG.15I depicts a side view of the housing as shown in FIG. 15H additionallyincluding the circuit board.

FIGS. 16A-16D illustrate multiple views of embodiments of aphysiological monitoring device. FIG. 16A shows a top perspective view,FIG. 16B shows a bottom view, FIG. 16C shows a top perspective viewincluding liners, FIG. 16D shows a bottom view including liners.

FIGS. 17A and 17B schematically illustrate cross-sectional views of twoexamples of an abrader. FIG. 17A depicts an abrader comprising acompressible spring. FIG. 17B depicts an abrader comprising acompressible foam.

FIG. 18 illustrates a schematic diagram of an embodiment of a cardiacrhythm inference service.

FIG. 19 is a schematic diagram of an embodiment of a system forextracting and transmitting data features from a physiological monitor.

DETAILED DESCRIPTION OF EMBODIMENTS

The following description is directed to a number of variousembodiments. The described embodiments, however, may be implementedand/or varied in many different ways. For example, the describedembodiments may be implemented in any suitable device, apparatus, orsystem to monitor any of a number of physiological parameters. Forexample, the following discussion focuses primarily on long-term,patch-based cardiac rhythm monitoring devices. In one alternativeembodiment, a physiological monitoring device may be used, for example,for pulse oximetry and diagnosis of obstructive sleep apnea. The methodof using a physiological monitoring device may also vary. In some cases,a device may be worn for one week or less, while in other cases, adevice may be worn for at least seven days and/or for more than sevendays, for example between fourteen days and twenty-one days or evenlonger.

Many other alternative embodiments and applications of the describedtechnology are possible. Thus, the following description is provided forexemplary purposes only. Throughout the specification, reference may bemade to the term “conformal.” It will be understood by one of skill inthe art that the term “conformal” as used herein refers to arelationship between surfaces or structures where a first surface orstructure adapts to the contours of a second surface or structure.

Since abnormal heart rhythms or arrhythmias can often be due to other,less serious causes, a key challenge is to determine when any of thesesymptoms are due to an arrhythmia. Oftentimes, arrhythmias occurinfrequently and/or episodically, making rapid and reliable diagnosisdifficult. As mentioned above, currently, cardiac rhythm monitoring isprimarily accomplished through the use of devices, such as Holtermonitors, that use short-duration (less than 1 day) electrodes affixedto the chest. Wires connect the electrodes to a recording device,usually worn on a belt. The electrodes need daily changing and the wiresare cumbersome. The devices also have limited memory and recording time.Wearing the device interferes with patient movement and often precludesperforming certain activities while being monitored, such as bathing.

Further, Holter monitors are capital equipment with limitedavailability, a situation that often leads to supply constraints andcorresponding testing delays. These limitations severely hinder thediagnostic usefulness of the device, the compliance of patients usingthe device, and the likelihood of capturing all important information.Lack of compliance and the shortcomings of the devices often lead to theneed for additional devices, follow-on monitoring, or other tests tomake a correct diagnosis.

Current methods to correlate symptoms with the occurrence ofarrhythmias, including the use of cardiac rhythm monitoring devices,such as Holter monitors and cardiac event recorders, are often notsufficient to allow an accurate diagnosis to be made. In fact, Holtermonitors have been shown to not lead to a diagnosis up to 90% of thetime (“Assessment of the Diagnostic Value of 24-Hour AmbulatoryElectrocardiographic Monitoring”, by DE Ward et al. Biotelemetry PatientMonitoring, vol. 7, published in 1980).

Additionally, the medical treatment process to actually obtain a cardiacrhythm monitoring device and initiate monitoring is typically verycomplicated. There are usually numerous steps involved in ordering,tracking, monitoring, retrieving, and analyzing the data from such amonitoring device. In most cases, cardiac monitoring devices used todayare ordered by a cardiologist or a cardiac electrophysiologist (EP),rather than the patient's primary care physician (PCP). This is ofsignificance since the PCP is often the first physician to see thepatient and determine that the patient's symptoms could be due to anarrhythmia. After the patient sees the PCP, the PCP will make anappointment for the patient to see a cardiologist or an EP. Thisappointment is usually several weeks from the initial visit with thePCP, which in itself leads to a delay in making a potential diagnosis aswell as increases the likelihood that an arrhythmia episode will occurand go undiagnosed. When the patient finally sees the cardiologist orEP, a cardiac rhythm monitoring device will usually be ordered. Themonitoring period can last 24 to 48 hours (Holter monitor) or up to amonth (cardiac event monitor or mobile telemetry device). Once themonitoring has been completed, the patient typically must return thedevice to the clinic, which itself can be an inconvenience. After thedata has been processed by the monitoring company or by a technicianon-site at a hospital or office, a report will finally be sent to thecardiologist or EP for analysis. This complex process results in fewerpatients receiving cardiac rhythm monitoring than would ideally receiveit.

To address some of these issues with cardiac monitoring, the assignee ofthe present application developed various embodiments of a small,long-term, wearable, physiological monitoring device. One embodiment ofthe device is the Zio® Patch. Various embodiments are also described,for example, in U.S. Pat. Nos. 8,150,502, 8,160,682 8,244,335,8,560,046, and 8,538,503, the full disclosures of which are herebyincorporated herein by reference. Generally, the physiologicalpatch-based monitors described in the above references fit comfortablyon a patient's chest and are designed to be worn for at least one weekand typically two to three weeks. The monitors detect and record cardiacrhythm signal data continuously while the device is worn, and thiscardiac rhythm data is then available for processing and analysis.

These smaller, long-term, patch-based physiological monitoring devicesprovide many advantages over prior art devices. At the same time,further improvements are desired. One of the most meaningful areas forimprovement is to offer more timely notice of critical arrhythmias tomanaging clinicians. The hallmark of these initial embodiments wasthat—for reasons of performance, compliance and cost—the device onlyrecorded information during the extended wear period, with analysis andreporting occurring after the recording completed. Thus, a desirableimprovement would be to add the capability of either real-time or timelyanalysis of the collected rhythm information. While diagnostic monitorswith such timely reporting capabilities currently exist, they requireone or more electrical components of the system to be either regularlyrecharged or replaced. These actions are associated with reduced patientcompliance and, in turn, reduced diagnostic yield. As such, a key areaof improvement is to develop a physiologic monitor that can combinelong-term recording with timely reporting without requiring batteryrecharging or replacement.

Patient compliance and device adhesion performance are two factors thatgovern the duration of the ECG record and consequently the diagnosticyield. Compliance can be increased by improving the patient's wearexperience, which is affected by wear comfort, device appearance, andthe extent to which the device impedes the normal activities of dailyliving. Given that longer ECG records provide greater diagnostic yieldand hence value, improvements to device adhesion and patient complianceare desirable.

Signal quality is important throughout the duration of wear, but may bemore important where the patient marks the record, indicating an area ofsymptomatic clinical significance. Marking the record is most easilyenabled through a trigger located on the external surface of the device.However, since the trigger may be part of a skin-contacting platformwith integrated electrodes, the patient can introduce significant motionartifacts when feeling for the trigger. A desirable device improvementwould be a symptom trigger that can be activated with minimal additionof motion artifact.

Further, it is desirable for the device to be simple and cost effectiveto manufacture, enabling scalability at manufacturing as well as higherquality due to repeatability in process. Simplicity of manufacture canalso lead to ease of disassembly, which enables the efficient recoveryof the printed circuit board for quality-controlled reuse in anotherdevice. Efficient reuse of this expensive component can be important fordecreasing the cost of the diagnostic monitor.

There remain clinical scenarios where still longer-duration andlower-cost solutions may be a valuable addition to a portfolio ofcardiac ambulatory monitoring options. Inspiration for a potentialsolution to these needs can be found in the continuous heart ratesensing functionality that is increasingly being incorporated in avariety of consumer health and fitness products, including smart watchesand wearable fitness bands. Although continuous heart rate data can beused to provide the user with information about their general fitnesslevels, it is more both more challenging and valuable to use this datato provide meaningful information related to their health and wellness.For example, the ability to detect potential arrhythmias from continuousheart rate data would enable consumer devices incorporating heart ratesensing functionality to serve as potential screening tools for theearly detection of cardiac abnormalities. Such an approach could beclinically valuable in providing a long-term, cost-effective screeningmethod for at-risk populations, for example, heart failure patients atrisk for Atrial Fibrillation. Alternatively, this monitoring approachcould be helpful in the long-term titration of therapeutic drug dosagesto ensure efficaciousness while reducing side effects, for example, inthe management of Paroxysmal Atrial Fibrillation. Beyond cardiacarrhythmia detection, the appropriate analysis of heart rate informationcould also yield insight into sleep and stress applications.

Long-term ambulatory monitoring with a physiologic device, such as anadhesive patch, has a number of clinical applications, particularly whentimely information about the occurrence and duration of observedarrhythmias can be provided during the monitoring period. In terms ofprevalence, particularly as driven by an aging population, efficientlydetecting Atrial Fibrillation (AF) remains the most significantmonitoring need. This need is not just evident for patients presentingwith symptoms, but also—given the increased risk of stroke associatedwith this arrhythmia—for broader, population-based monitoring ofasymptomatic AF in individuals at risk due to one or more factors ofadvanced age, the presence of chronic illnesses like Heart Disease, oreven the occurrence of surgical procedures. For the latter group, bothperioperative and post-procedure monitoring can be clinically valuable,and not just for procedures targeted at arrhythmia prevention (forexample, the MAZE ablation procedure, or hybrid endo and epicardialprocedures, both for treatment of AF), but also for general surgeriesinvolving anesthesia. For some applications, the goal of ambulatorymonitoring for Atrial Fibrillation will sometimes be focused on thesimple binary question of yes or no—did AF occur in a given time period.For example, monitoring a patient following an ablation procedure willtypically seek to confirm success, typically defined as the completelack of AF occurrence. Likewise, monitoring a patient post-stroke willbe primarily concerned with evaluating the presence of AtrialFibrillation.

However, even in those scenarios, if AF occurs, it may be clinicallymeaningful to evaluate additional aspects to better characterize theoccurrence, such as daily burden (% of time in AF each day), andduration of episodes (expressed, for example, as a histogram of episodeduration, or as the percentage of episodes that extend beyond aspecified limit, say six minutes), both either in absolute terms or incomparison to prior benchmarks (for example, from a baseline,pre-procedure monitoring result). Indeed, measuring daily AF burden,evaluating AF episode duration, and reviewing AF occurrence during sleepand waking periods, and evaluating the presence of AF in response to thedegree of a patient's physical movement can be important in a variety ofclinical scenarios, including evaluating the effectiveness of drug-basedtreatment for this arrhythmia.

Making this information available in a timely manner during themonitoring period could allow the managing physician to iterativelytitrate treatment, for example, by adjusting the dosage and frequency ofa novel oral anticoagulant drug (NOAC) until management was optimized. Afurther example of this management paradigm is for the patient to benotified of asymptomatic AF—either directly by the device throughaudible or vibration-based alert, through notification from anapplication connected to the device, or via phone, email or text-messagecommunication from the managing clinician—for the timely application ofa “pill in the pocket” for AF management.

The theme of timely management and/or intervention is certainly evidentin situations where clinically significant arrhythmias are observed, forexample, asymptomatic second-degree and complete Heart Block, extendedpauses, high-rate supraventricular tachycardias, prolonged ventriculartachycardias, and ventricular fibrillation. For example, the clinicalscenario where an extended pause or complete heart block causes Syncopeis a particularly significant case where the availability of a timelyand dependable monitoring method could reduce or even eliminate the needfor in-hospital monitoring of at-risk patients. The theme can alsoextend to more subtle changes in morphology, for example, QTprolongation in response to medications, which has been shown to havesignificant cardiac safety implications. Timely awareness of suchprolongation could lead, for example, to early termination of clinicalstudies evaluating drug safety and effectiveness or, alternatively, toadjusting the dosage or frequency as a means to eliminate observedprolongation.

Physiological Monitoring Devices

Referring to FIGS. 1A and 1B, perspective and exploded profile views ofone embodiment of a physiological monitoring device 100 are provided. Asseen in FIG. 1A, physiological monitoring device 100 may include aflexible body 110 coupled with a watertight, housing 115. As will beunderstood by one of skill in the art, the housing as described hereinand throughout this specification, may be constructed from rigid orflexible materials, thereby rendering the housing rigid, such as toresist deformation or soft such as to flex and/or deform with force.Flexible body 110 (which may be referred to as “flexible substrate” or“flexible construct”) typically includes two wings 130, 131, whichextend laterally from housing 115, and two flexible electrode traces311, 312, each of which is embedded in one of wings 130, 131. Eachelectrode trace 311, 312 is coupled, on the bottom surface of flexiblebody 110, with a flexible electrode (not visible in FIG. 1A). Theelectrodes are configured to sense heart rhythm signals from a patientto which monitoring device 100 is attached. Electrode traces 311, 312then transmit those signals to electronics (not visible in FIG. 1A)housed in housing 115. Housing 115 also typically contains a powersource, such as one or more batteries.

The combination of a highly flexible body 110, including flexibleelectrodes and electrode traces 311, 312, with a very housing 115 mayprovide a number of advantages. A key advantage is high fidelity signalcapture. The highly conformal and flexible wings 130, 131, electrodesand traces 311, 312 limit the transmission of external energy to theelectrode-skin interface. If motion is imparted to the housing 115, forexample, the system of conformal adhesion to the skin limits the extentto which that motion affects the monitored signal. Flexible electrodetraces 311, 312 generally may help provide conformal contact with thesubject's skin and may help prevent electrodes 350 (electrodes 350 arenot visible in FIG. 1, but are visible in FIG. 6A described below) frompeeling or lifting off of the skin, thereby providing strong motionartifact rejection and better signal quality by minimizing transfer ofstress to electrodes 350. Furthermore, flexible body 110 includes aconfiguration and various features that facilitate comfortable wearingof device 100 by a patient for fourteen (14) days or more withoutremoval. Housing 115, which typically does not adhere to the patient inthe embodiments described herein, includes features that lend to thecomfort of device 100. Hinge portions 132 are relatively thin, even moreflexible portions of flexible body 110. They allow flexible body 110 toflex freely at the area where it is joined to housing 115. Thisflexibility enhances comfort, since when the patient moves, housing 115can freely lift off of the patient's skin. Electrode traces 311, 312 arealso very thin and flexible, to allow for patient movement withoutsignal distortion.

Referring now to FIG. 1B, a partially exploded view of physiologicalmonitoring device 100 illustrates component parts that make up, and thatare contained within, housing 115 in greater detail. In this embodiment,housing 115 includes an upper housing member 140, which detachablycouples with a lower housing member 145. Sandwiched between upperhousing member 140 and lower housing member 145 are an upper gasket 370,and a lower gasket 360 (not visible on FIG. 1B but just below uppergasket 370). Gaskets 370, 360 help make housing member and/or body 115watertight when assembled. A number of components of monitoring device100 may be housed between upper housing member 140 and lower housingmember 145. For example, in one embodiment, housing 115 may contain aportion of flexible body 110, a printed circuit board assembly (PCBA)120, a battery holder 150, and two batteries 160. Printed circuit boardassembly 120 is positioned within housing 115 to contact electrodetraces 311, 312 and batteries 160. In various embodiments, one or moreadditional components may be contained within or attached to housing115. Some of these optional components are described further below, inreference to additional drawing figures.

Battery holder 150, according to various alternative embodiments, mayhold two batteries (as in the illustrated embodiment), one battery, ormore than two batteries. In other alternative embodiments, other powersources may be used. In the embodiment shown, battery holder 150includes multiple retain tabs and/or protrusions 153 for holdingbatteries 160 in holder 150. Additionally, battery holder 150 includesmultiple feet and/or protrusions 152 to establish correct spacing ofbatteries 160 from the surface of PCBA 120 and ensure proper contactwith spring fingers and/or contacts 235 and 236. Spring fingers 235 and236 are used in this embodiment rather than soldering batteries 160 toPCBA 120. Although soldering may be used in alternative embodiments, oneadvantage of spring fingers 235 and 236 is that they allow batteries 160to be removed from PCBA 120 and holder 150 without damaging either ofthose components, thus allowing for multiple reuses of both Eliminatingsolder connections also simplifies and speeds up assembly anddisassembly of monitoring device 100.

In some embodiments, upper housing member 140 may act as a patient eventtrigger. When a patient is wearing physiological monitoring device 100for cardiac rhythm monitoring, it is typically advantageous for thepatient to be able to register with device 100 (for example, log intothe device's memory) any cardiac events perceived by the patient. If thepatient feels what he/she believes to be an episode of heart arrhythmia,for example, the patient may somehow trigger device 100 and thus providea record of the perceived event. In some embodiments, trigger ofperceived events by the patient may initiate transmission of dataassociated with the triggered event. In some embodiments, trigger ofperceived events may simply mark a continuous record with the locationof the triggered event. In some embodiments, both transmission ofassociated data as well as marking of the continuous record may occur.At some later time, the patient's recorded symptom during the perceivedevent could be compared with the patient's actual heart rhythm, recordedby device 100, and this may help determine whether the patient'sperceived events correlate with actual cardiac events. One problem withpatient event triggers in currently available wearable cardiac rhythmmonitoring devices, however, is that a small trigger may be hard to findand/or activate, especially since the monitoring device is typicallyworn under clothing. Additionally, pressing a trigger button may affectthe electronics and/or the electrodes on the device in such a way thatthe recorded heart rhythm signal at that moment is altered simply by themotion caused to the device by the patient triggering. For example,pressing a trigger may jar one or both of the electrodes in such a waythat the recorded heart rhythm signal at that moment appears like anarrhythmia, even if no actual arrhythmia event occurred. Additionally,there is a chance that the trigger may be inadvertently activated, forinstance while sleeping or laying on the monitoring device.

In the embodiment shown in FIGS. 1A and 1B, however, housing 115 issufficiently rigid, and flexible body 110 is sufficiently flexible, thatmotion applied to housing 115 by a patient may rarely or ever cause anaberrant signal to be sensed by the electrodes. In this embodiment, thecentral portion of upper housing member 140 is slightly concave and,when pressed by a patient who is wearing device 100, this centralportion depresses slightly to trigger a trigger input on PCBA 120.Because the entire upper surface of housing 115 acts as the patientevent trigger, combined with the fact that it is slightly concave, itwill generally be quite easy for a patient to find and push down thetrigger, even under clothing. Additionally, the concave nature of thebutton allows it to be recessed which protects it from inadvertentactivations. Thus, the present embodiment may alleviate some of theproblems encountered with patient event triggers on currently availableheart rhythm monitors. These and other aspects of the features shown inFIGS. 1A and 1B will be described in further detail below.

Referring now to the embodiments in FIGS. 2A and 2B, printed circuitboard assembly 120 (or PCBA) may include a top surface 220, a bottomsurface 230, a patient trigger input 210 and spring contacts 235, 236,and 237. Printed circuit board assembly 120 may be used to mechanicallysupport and electrically connect electronic components using conductivepathways, tracks or electrode traces 311, 312. Furthermore, because ofthe sensitive nature of PCB A 120 and the requirement to mechanicallyinterface with rigid body 115, it is beneficial to have PCBA 120 besubstantially rigid enough to prevent unwanted deflections which mayintroduce noise or artifact into the ECG signal. This is especiallypossible during patient trigger activations when a force is transmittedthrough rigid body 115 and into PCBA 120. One way to ensure rigidity ofthe PCBA is in some embodiments, to ensure that the thickness of thePCBA is relatively above a certain value. For example, a thickness of atleast about 0.08 cm is desirable and, more preferably, a thickness of atleast about 0.17 cm is desirable. In this application, PCBA 120 may alsobe referred to as, or substituted with, a printed circuit board (PCB),printed wiring board (PWB), etched wiring board, or printed circuitassembly (PCA). In some embodiments, a wire wrap or point-to-pointconstruction may be used in addition to, or in place of, PCBA 120. PCBA120 may include analog circuits and digital circuits.

Patient trigger input 210 may be configured to relay a signal from apatient trigger, such as upper housing member 140 described above, toPCBA 120. For example, patient trigger input 210 may be a PCB switch orbutton that is responsive to pressure from the patient trigger (forexample, the upper surface of upper housing portion 140). In variousembodiments, patient trigger input 210 may be a surface mounted switch,a tactile switch, an LED illuminated tactile switch, or the like. Insome embodiments, patient trigger input 210 may also activate anindicator, such as an LED. Certain embodiments may involve a remotelylocated trigger such as on a separate device or as a smart phone app.

One important challenge in collecting heart rhythm signals from a humanor animal subject with a small, two-electrode physiological monitoringdevice such as device 100 described herein, is that having only twoelectrodes can sometimes provide a limited perspective when trying todiscriminate between artifact and clinically significant signals. Forexample, when a left-handed patient brushes her teeth while wearing asmall, two-electrode physiological monitoring device on her left chest,the tooth brushing may often introduce motion artifact that causes arecorded signal to appear very similar to Ventricular Tachycardia, aserious heart arrhythmia. Adding additional leads (and, hence, vectors)is the traditional approach toward mitigating this concern, but this istypically done by adding extra wires adhered to the patient's chest invarious locations, such as with a Holter monitor. This approach is notconsistent with a small, wearable, long term monitor such asphysiological monitoring device 100.

An alternate approach to the problem described above is to provide oneor more additional data channels to aid signal discrimination. In someembodiments, for example, device 100 may include a data channel fordetecting patch motion. In certain embodiments, an accelerometer orother suitable device may provide patch motion by simply analyzing thechange in magnitude of a single axis measurement, or alternatively ofthe combination of all three axes. The accelerometer may record devicemotion at a sufficient sampling rate to allow algorithmic comparison ofits frequency spectrum with that of the recorded ECG signal. If there isa match between the motion and recorded signal, it is clear that thedevice recording in that time period is not from a clinical (forexample, cardiac) source, and thus that portion of the signal can beconfidently marked as artifact. This technique may be particularlyuseful in the tooth brushing motion example aforementioned, where therapid frequency of motion as well as the high amplitude artifact issimilar to the heart rate and morphology, respectively, of a potentiallylife-threatening arrhythmia like Ventricular Tachycardia. Other suitabledevices described herein this section and elsewhere in the specificationmay also be utilized to provide motion information.

In some embodiments, using the magnitude of all three axes for such ananalysis would smooth out any sudden changes in values due to a shift inposition rather than a change in activity. In some embodiments, theremay be some advantage in using a specific axis of measurement such asalong the longitudinal axis of the body to focus on a specific type ofartifact introduced by upward and downward movements associated withwalking or running. In a similar vein, the use of a gyroscope inconjunction with the accelerometer may provide further resolution as tothe nature of the motion experienced. While whole body movements may besufficiently analyzed with an accelerometer on its own, specific motionof interest such as rotational motion due to arm movement issufficiently complex that an accelerometer alone might not be able todistinguish.

In addition to detecting motion artifact, an accelerometer tuned to thedynamic range of human physical activities may provide activity levelsof the patient during the recording, which can also enhance accuracy ofalgorithmic true arrhythmia detection. Given the single-lead limitationof device 100, arrhythmias that require observation of less prominentwaves (for example P-wave) in addition to rate changes such asSupraventricular Tachycardia pose challenges to both computerizedalgorithms as well as the trained human eye. This particular arrhythmiais also characterized by the sudden nature of its onset, which may bemore confidently discriminated from a non-pathological Sinus Tachycardiaif a sudden surge in the patient's activity level is detected at thesame time as the increase in heart rate. Broadly speaking, the provisionof activity information to clinical professionals may help themdiscriminate between exercise-induced arrhythmia versus not. As withmotion artifact detection, a single-axis accelerometer measurementoptimized to a particular orientation may aid in more specificallydetermining the activity type such as walking or running. Thisadditional information may help explain symptoms more specifically andthereby affect the subsequent course of therapeutic action.

In certain embodiments, an accelerometer with 3 axes may conferadvantages beyond what magnitude of motions can provide. When thesubject is not rapidly moving, 3-dimensional accelerometer readings mayapproximate the tilt of PCBA 120, and therefore body orientationrelative to its original orientation. The original body orientation canbe assumed to be in either an upright or supine position which isrequired for appropriate positioning and application of the device tothe body. This information may aid in ruling out certain cardiacconditions that manifest as beat-to-beat morphology changes, such ascardiac alternans where periodic amplitude changes are observed, oftenin heart failure cases. Similar beat-to-beat morphology changes areobservable in healthy subjects upon shift in body position due to theshift in heart position relative to the electrode vector, for examplefrom an upright to a slouching position. By design, the single-channeldevice 100 does not have an alternate ECG channel to easily rule outpotential pathological shifts in morphology, however, correlation withshifts in body orientation will help explain these normal changes andavoid unnecessary treatment due to false diagnosis.

In some embodiments, the accelerometer may also be used as a sleepindicator, based on body orientation and movement. When presentingclinical events (for example, pauses), it is diagnostically helpful tobe able to present information in a manner that clearly separates eventsthat occurred during sleep from those during waking hours. In fact,certain algorithms such as for ECG-derived respiratory rate only makesense to run when the patient is in a relatively motionless state andtherefore subtle signal modulation introduced by chest movement due tobreathing is observable. Respiratory rate information is useful as onechannel of information necessary to detect sleep apnea in certainpatient populations.

In certain embodiments, the accelerometer may also be used to detectfree-falls, such as fainting. With an accelerometer, device 100 may beable to mark fainting (syncope) and other free-fall events withoutrelying on patient trigger. In some embodiments, such free-fall eventtriggers may initiate transmission of associated data. In order to allowtimely detection of such critical events, yet considering the batteryand memory limitations of a small, wearable device such as device 100,acquisition of accelerometer readings may be done in bursts, where onlyinteresting information such as a potential free fall is written tomemory at a high sampling rate. An expansion of this event-triggerconcept is to use specific tapping motions on device 100 as a patienttrigger instead of or in conjunction with the button previouslydescribed. The use and detection of multiple types of tapping sequencesmay provide better resolution and accuracy into what exactly the patientwas feeling, instead of relying on the patient to manually record theirsymptom and duration in a trigger log after the fact. An example of suchadded resolution is to indicate the severity of the symptom by thenumber of sequential taps.

Alternatively, in some embodiments, optical sensors may be used todistinguish between device motion and patient body motion. Further, inadditional embodiments, the device may not require a button or trigger.In still more embodiments, suitable devices described herein thissection or elsewhere in the specification may also be used.

Another optional data channel that may be added to physiologicalmonitoring device 100 is a channel for detecting flex and/or bend ofdevice 100. In various embodiments, for example, device 100 may includea strain gauge, piezoelectric sensor or optical sensor to detect motionartifact in device 100 itself and thus help to distinguish betweenmotion artifact and cardiac rhythm data. Yet another optional datachannel for device 100 may be a channel for detecting heart rate. Forexample, a pulse oximeter, microphone or stethoscope may provide heartrate information. Redundant heart rate data may facilitatediscrimination of ECG signals from artifact. This is particularly usefulin cases where arrhythmia such as Supraventricular Tachycardia isinterrupted by artifact, and decisions must be made whether the episodewas actually multiple shorter episodes or one sustained episode. Anotherdata channel may be included for detecting ambient electrical noise. Forexample, device 100 may include an antenna for picking upelectromagnetic interference. Detection of electromagnetic interferencemay facilitate discrimination of electrical noise from real ECG signals.Any of the above-described data channels may be stored to support futurenoise discrimination or applied for immediate determination of clinicalvalidity in real-time.

With reference now to the embodiments of FIGS. 3A and 3B, flexible body110 is shown in greater detail. As illustrated in FIG. 3A, flexible body110 may include wings 130, 131, a thin border 133 (or “rim” or “edge”)around at least part of each wing 130, 131, electrode traces 311, 312,and a hinge portion 132 (or “shoulder”) at or near a junction of eachwing 130, 131 with housing 115. Also shown in FIG. 3A is upper gasket370, which is not considered part of flexible body 110 for thisdescription, but which facilitates attachment of flexible body 110 tohousing 115.

Hinge portions 132 are relatively thin, even more flexible portions offlexible body 110. They allow flexible body 110 to flex freely at thearea where it is joined to housing 115. This flexibility enhancescomfort, since when the patient moves, housing 115 can freely lift offof the patient's skin. Electrode traces 311, 312 are also very thin andflexible, to allow for patient movement without signal distortion.Borders 133 are portions of flexible body 110 that is thinner thanimmediately adjacent portions and that provide for a smooth transitionfrom flexible body 110 to a patient's skin, thus preventing edge-liftand penetration of dirt or debris below flexible body 110.

As shown in greater detail in FIG. 3B, flexible body 110 may includemultiple layers. As mentioned previously, in some embodiments, uppergasket 370 and lower gasket 360 are not considered part of flexible body110 for the purposes of this description but are shown for completenessof description. This distinction is for ease of description only,however, and should not be interpreted to limit the scope of thedescribed embodiments. Flexible body 110 may include a top substratelayer 300, a bottom substrate layer 330, an adhesive layer 340, andflexible electrodes 350. Top and bottom substrate layers 300, 330 may bemade of any suitable, flexible material, such as one or more flexiblepolymers. Suitable flexible polymers can include, but are not limitedto, polyurethane, polyethylene, polyester, polypropylene, nylon, teflonand carbon impregnated vinyl. The material of substrate layers 300, 330may be selected based on desired characteristics. For example, thematerial of substrate layers 300, 330 may be selected for flexibility,resilience, durability, breathability, moisture transpiration, adhesionand/or the like. In one embodiment, for example, top substrate layer 300may be made of polyurethane, and bottom substrate layer 330 may be madeof polyethylene or alternatively polyester. In some embodiments,substrate layers 300, 330 may be made of the same material. In yetanother embodiment, substrate layer 330 may contain a plurality ofperforations in the area over adhesive layer 340 to provide for evenmore breathability and moisture transpiration. In various embodiments,physiological monitoring device 100 may be worn continuously by apatient for as many as 14-21 days or more, without removal during thetime of wear and with device 100 being worn during showering, exercisingand the like. Thus, the material(s) used and the thickness andconfiguration of substrate layers 300, 330 affect the function ofphysiological monitoring device 100. In some embodiments, the materialof substrate layers 300, 330 acts as an electric static discharge (ESD)barrier to prevent arcing.

Typically, top and bottom substrate layers 300, 330 are attached to oneanother via adhesive placed on one or both layers 300, 330. For example,the adhesive or bonding substance between substrate layers 300, 330 maybe an acrylic-based, rubber-based, or silicone-based adhesive. In otheralternative embodiments, flexible body 110 may include more than twolayers of flexible material.

In addition to the choice of material(s), the dimensions, such asthickness, length and width, of substrate layers 300, 330 may beselected based on desired characteristics of flexible body 110. Forexample, in various embodiments, the thickness of substrate layers 300,330 may be selected to give flexible body 110 an overall thickness ofbetween about 0.1 mm to about 1.0 mm. According to various embodiments,flexible body 110 may also have a length of between about 7 cm and 15 cmand a width of about 3 cm and about 6 cm. Generally, flexible body 110will have a length sufficient to provide a necessary amount ofseparation between electrodes 350. For example, in one embodiment adistance from the center of one electrode 350 to the center of the otherelectrode 350 should be at least about 6.0 cm and more preferably atleast about 8.5 cm. This separation distance may vary, depending on theapplication. In some embodiments, substrate layers 300, 330 may all havethe same thickness. Alternatively, the two substrate layers 300, 330 mayhave different thicknesses.

As mentioned above, hinge portions 132 allow the rigid body 115 to liftaway from the patient while flexible body 110 remains adhered to theskin. The functionality of hinge portions 132 is critical in allowingthe device to remain adhered to the patient throughout variousactivities that may stretch and compress the skin. Furthermore, hingeportions 132 allow for significantly improved comfort while wearing thedevice. Generally, hinge portions 132 will be sufficiently wide enoughto provide adequate lift of rigid body 115 without creating too large ofa peel force on flexible body 110. For example, in various embodiments,the width of hinge portion 132 should be at least about 0.25 cm and morepreferably at least about 0.75 cm.

Additionally, the shape or footprint of flexible body 110 may beselected based on desired characteristics. As seen in FIG. 3A, wings130, 131 and borders 133 may have rounded edges that give flexible body110 an overall “peanut” shape. However, wings 130, 131 can be formed inany number of different shapes such as rectangles, ovals, loops, orstrips. In the embodiment shown in FIGS. 3A and 3B, the footprint topsubstrate layer 300 is larger than the footprint of bottom substratelayer 330, with the extension of top substrate layer 300 forming borders133. Thus, borders 133 are made of the same polyurethane material thattop layer 300 is made of. Borders 133 are thinner than an adjacentportion of each wing 130, 131, since they include only top layer 300.The thinner, highly compliant rim and/or border 133 will likely enhanceadherence of physiologic monitoring device 100 to a patient, as itprovides a transition from an adjacent, slightly thicker portion ofwings 130, 131 to the patient's skin and thus helps prevent the edge ofdevice 100 from peeling up off the skin. Border 133 may also helpprevent the collection of dirt and other debris under flexible body 110,which may help promote adherence to the skin and also enhance theaesthetics of device 100. In alternative embodiments, the footprint ofsubstrate layers 300, 330 may be the same, thus eliminating borders 133.

While the illustrated embodiments of FIGS. 1A-3B include only two wings130, 131, which extend from housing 115 in approximately oppositedirections (for example, at a 180-degree angle relative to each other),other configurations are possible in alternative embodiments. Forexample, in some embodiments, wings 130, 131 may be arranged in anasymmetrical orientation relative to one another and/or one or moreadditional wings may be included. As long as sufficient electrodespacing is provided to permit physiological signal monitoring, and aslong as wings 130, 131 are configured to provide extended attachment tothe skin, any suitable configuration and number of wings 130, 131 andelectrode traces 311, 312 may be used. The embodiments described abovehave proven to be advantageous for adherence, patient comfort andaccuracy of collected heart rhythm data, but in alternative embodimentsit may be possible to implement alternative configurations.

Adhesive layer 340 is an adhesive that is applied to two portions of thebottom surface of bottom substrate layer 330, each portion correspondingto one of wings 130, 131. Adhesive layer 340 thus does not extend alongthe portion of bottom substrate layer 330 upon which housing 115 ismounted. Adhesive layer 340 may be made of any suitable adhesive,although certain adhesives have been found to be advantageous forproviding long term adhesion to patient skin with relative comfort andlack of skin irritation. For example, in one embodiment, adhesive layer340 is a hydrocolloid adhesive. In another embodiment, the adhesivelayer 340 is comprised of a hydrocolloid adhesive that containsnaturally-derived or synthetic absorbent materials which take upmoisture from the skin during perspiration.

With reference now to FIG. 3B, each of the two portions of adhesivelayer 340 includes a hole, into which one of electrodes 350 fits.Electrodes 350 are made of flexible material to further provide foroverall conformability of flexible body 110. In one embodiment, forexample, flexible electrodes 350 may be made of a hydrogel electrode350. Electrodes 350 generally provide conformal, non-irritating contactwith the skin to provide enhanced electrical connection with the skinand reduce motion artifact. In some embodiments, hydrogel electrodes 350may be punched into adhesive layer 340, thus forming the holes andfilling them with hydrogel electrodes 350. In one alternativeembodiment, electrodes 350 and adhesive 340 may be replaced with anadhesive layer made of a conductive material, such that the entireadhesive layer on the underside of each wing 130, 131 acts as anelectrode. Such an adhesive layer may include a hybridadhesive/conductive substance or adhesive substance mixed withconductive elements or particles. For example, in one embodiment, suchan adhesive layer may be a hybrid of a hydrogel and a hydrocolloidadhesive. Housing 115 of FIG. 1A also protects the electronics and powersource contained in housing 115, enhances the ability of a patient toprovide an input related to a perceived cardiac event, and allows forsimple manufacturing and reusability of at least some of the contents ofhousing 115. These and other features of physiological monitoring device100 are described in greater detail below.

As discussed above, in some embodiments, adhesive layer 340 may cover aportion of the underside of lower substrate layer 330, such that atleast a portion of the bottom side of flexible body 110 does not includeadhesive layer 340. As seen in FIG. 3A, hinges 132 may be formed in theflexible body 110 as portions of each wing 130, 131 on which adhesivelayer 340 is not applied. Hinge portions 132 are generally located at ornear the junction of flexible body 110 with housing 115, and thusprovide for flexing of device 100 to accommodate patient movement. Insome embodiments, hinge portions 132 may have a width that is less thanthat of adjacent portions of wings 130, 131, thus giving device 100 its“peanut” shape mentioned above. As shown in FIG. 8, as a subject moves,device 100 flexes along with patient movement. Device flexion may besevere and is likely to occur many times during long term monitoring.Hinge portions 132 may allow for dynamic conformability to the subject,while the rigidity of housing 115 may allow housing 115 to pop up offthe patient's skin during device flexion, thus preventing peeling of thedevice 100 off of the skin at its edge.

Flexible body 110 further includes two electrode traces 311, 312sandwiched between upper substrate layer 300 and lower substrate layer330. Each electrode trace 311, 312 may include an electrode interfaceportion 310 and an electrocardiogram circuit interface portion 313. Asillustrated in the embodiments of FIGS. 3C and 3D, ECG circuit interfaceportions 313 are in physical contact with spring fingers 237 and provideelectrical communication with PCBA 120 when device 100 or zoomed-indevice portion 101 is assembled. Electrode interface portions 310contact hydrogel electrodes 350. Thus, electrode traces 311, 312transmit cardiac rhythm signals (and/or other physiological data invarious embodiments) from electrodes 350 to PCBA 120.

The material and thickness of electrode traces 311, 312 are importantfor providing a desired combination of flexibility, durability andsignal transmission. For example, in one embodiment, electrode traces311, 312 may include a combination of silver (Ag) and silver chloride(AgCl). The silver and silver chloride may be disposed in layers. Forexample, one embodiment of electrode traces 311, 312 may include a toplayer of silver, a middle layer of carbon impregnated vinyl, and abottom (patient-facing) layer of silver chloride. In another embodiment,both top and bottom layers of electrode traces 311, 312 may be made ofsilver chloride. In one embodiment, the top and bottom layers may beapplied to the middle layer in the form of silver ink and silverchloride ink, respectively. In an alternative embodiment, each electrodetrace may include only two layers, such as a top layer of silver and abottom layer of silver chloride. In various embodiments, the material ofa bottom layer of each electrode trace 311, 312, such as AgCl, may beselected to match the chemistry of the hydrogel electrodes 350 andcreate a half-cell with the body of the subject.

The thickness of the electrode traces 311, 312 may be selected tooptimize any of a number of desirable properties. For example, in someembodiments, at least one of the layers of electrode traces 311, 312 canbe of a sufficient thickness to minimize or slow depletion of thematerial from an anode/cathode effect over time. Additionally, thethickness may be selected for a desired flexibility, durability and/orsignal transmission quality.

As mentioned above, in some embodiments, top gasket 370 and bottomgasket 360 may be attached upper substrate 300 and lower substrate 330of flexible body 110. Gaskets 360, 370 may be made of any suitablematerial, such as urethane, which provides a watertight seal between theupper housing member 140 and lower housing member 145 of housing 115. Inone embodiment, top gasket 370 and/or bottom gasket 360 may include anadhesive surface. FIG. 3E depicts yet another embodiment where topgasket 370 includes tabs 371 that protrude away from the profile of tophousing 140 while still being adhered to upper substrate 300. The tabs371 cover a portion of electrode traces 311, 312 and provide a strainrelief for the traces at the point of highest stress where the flexiblebody meets the housing.

With reference now to the embodiment of FIG. 4, upper housing member 140and lower housing member 145 of housing 115 are shown in greater detail.Upper and lower housing members 140, 145 may be configured, when coupledtogether with gaskets 360, 370 in between, to form a watertightenclosure for containing PCBA 120, battery holder 150, batteries 160 andany other components contained within housing 115. Housing members 140,145 may be made of any suitable material to protect internal components,such as water-resistant plastic. In one embodiment, upper housing member140 may include a rigid sidewall and/or hook 440, a light pipe 410 totransmit visual information from the LEDs on the PCBA through thehousing member, a slightly flexible top surface 420, and an innertrigger member 430 extending inward from top surface 420. Top surface420 is configured to be depressed by a patient when the patientperceives what he or she believes to be an arrhythmia or other cardiacevent. When depressed, top surface 420 depresses inner trigger member430, which contacts and activates trigger input 210 of PCBA 120.Additionally, as discussed previously, top surface 420 may have aconcave shape (concavity facing the inside of housing 115) toaccommodate the shape of a finger. It is believed that the design ofupper housing member 140 isolates activation of the trigger input 210from electrodes 350, thereby minimizing artifact in the data recording.

With continued reference to FIG. 4, lower housing member 145 may beconfigured to detachably connect with upper housing member 140 in such away that housing members 140, 145 may be easily attached and detachedfor reusability of at least some of the component parts of monitoringdevice 100. In some embodiments, a bottom surface 445 (patient facingsurface) of lower housing member 145 may include multiple dimples 450(or “bumps,” “protrusions” or the like), which will contact thepatient's skin during use. Dimples 450 may allow for air flow betweenbottom surface 445 and the patient's skin, thus preventing a seal fromforming between bottom surface 445 and the skin. It is believed thatdimples 450 improve comfort and help prevent a perception in currentlyavailable devices in which the patient feels as if monitoring device 100is falling off when the housing 115 lifts off the skin and breaks a sealwith the skin. In yet another embodiment the bottom surface 445 of lowerhousing member 145 may include multiple divots (recesses instead ofprotrusions) to prevent a seal from forming.

Referring now to the embodiment of FIG. 5A, battery holder 150 is shownin greater detail. Battery holder 150 may be made of plastic or othersuitable material, is configured to be mounted to PCBA 120 andsubsequently attached to housing 115, and is capable of holding twobatteries 160 (FIG. 1B). In alternative embodiments, battery holder 150may be configured to hold one battery or more than two batteries. Aplurality of protrusions 152 provide a stable platform for batteries 160to be positioned a fixed distance above the surface of PCBA 120,avoiding unwanted contact with sensitive electronic components yetproviding for adequate compression of spring contacts 235 (FIG. 5B).Protrusions 153 lock batteries 160 into position and resist the upwardforce on the batteries from spring contacts 235. Battery holder 150 alsopositions batteries appropriately 160 to provide for adequatecompression of spring contacts 236. Use of battery holder 150 inconjunction with spring contacts 235 and 236 allows for batteries 160 tobe electrically connected to PCBA 120 while still having additionalelectronic components between batteries 160 and PCBA 120 and maintain avery compact assembly. Battery holder 150 may include a flexible hook510 which engages a corresponding rigid hook 440 of upper housing member140. Under normal assembly conditions the flexible hook 510 remainssecurely mated with rigid hook 440. For disassembly, flexible hook 510can be pushed and bent using an appropriate tool passed through tophousing 140 causing it to disengage from rigid hook 440 and subsequentlyallow top housing 140 to be removed.

With reference now to the embodiments of FIGS. 6A and 6B, physiologicalmonitoring device 100 is shown in the side view cross-section. As shownin 6A, physiological monitoring device 100 may include flexible body 110coupled with housing 115. Flexible body 110 may include top substratelayer 300, bottom substrate layer 330, adhesive layer 340 and electrodes350. Electrode traces 311, 312 are also typically part of flexible body110 and are embedded between top substrate layer 300 and bottomsubstrate layer 330, but they are not shown in FIG. 6. Flexible body 110forms two wings 130, 131, extending to either side of housing 115, and aborder 133 surrounding at least part of each wing 130, 131. Housing 115may include an upper housing member 140 coupled with a lower housingmember 145 such that it sandwiches a portion of flexible body 110 inbetween and provides a watertight, sealed compartment for PCBA 120.Upper housing member 140 may include inner trigger member 430, and PCBAmay include patient trigger member 210. As discussed previously, lowerhousing member 145 may include multiple dimples 450 or divots to enhancethe comfort of the monitoring device 100.

It is desirable that PCBA 120 is sufficiently rigid to prevent bendingand introducing unwanted artifact into the signal. In certainembodiments, an additional mechanism to reduce and prevent unwantedbending of PCBA 120 may be used. This mechanism is shown in FIG. 6B.Support post 460 is integral to lower housing 145 and is positioneddirectly under patient trigger input 210. During patient symptomtriggering, upper housing member 140 is depressed, engaging innertrigger mechanism 430 and transmitting a force through patient triggerinput 210 into PCBA 120. The force is further transmitted through PCBA120 and into support post 460 without creating a bending moment, thusavoiding unwanted artifact.

Referring to FIG. 7, in some embodiments, physiological monitoringdevice 100 may include one or more additional, optional features. Forexample, in one embodiment, monitoring device 100 may include aremovable liner 810, a top label 820, a device identifier 830 and abottom label 840. Liner 810 may be applied over a top surface offlexible member and/or body 110 to aid in the application of device 100to the subject. As is described in further detail below, liner 810 mayhelp support borders 133 of flexible body 110, as well as wings 130,131, during removal of one or more adhesive covers (not shown) thatcover adhesive surface 340 before use. Liner 810 may be relative rigidand/or firm, to help support flexible body 110 during removal ofadhesive covers. In various embodiments, for example, liner 810 may bemade of cardboard, thick paper, plastic or the like. Liner 810 typicallyincludes an adhesive on one side for adhering to the top surface ofwings 130, 131 of flexible body 110.

Labels 820, 840 may be any suitable labels and may include producename(s), manufacturer name(s), logo(s), design(s) and/or the like. Theymay be removable or permanently attached upper housing member 140 and/orlower housing member 145, although typically they will be permanentlyattached, to avoid unregulated reuse and/or resale of the device by anunregistered user. Device identifier 830 may be a barcode sticker,computer readable chip, RFID, or the like. Device identifier 830 may bepermanently or removably attached to PCBA 120, flexible body 110 or thelike. In some embodiments, it may be beneficial to have deviceidentifier 830 stay with PCBA 120.

Referring now to the embodiments of FIGS. 8A and 8B, physiologicalmonitoring device 100 generally includes hinge portions 132 at or nearthe juncture of each wing 130, 131 with housing 115. Additionally, eachwing 130, 131 is typically adhered to the patient via adhesive layers340, while rigid body 115 is not adhered to the patient and is thus freeto “float” (for example, move up and down) over the patient's skinduring movement and change of patient position. In other words, when thepatient's chest contracts, housing pops up or floats over the skin, thusminimizing stress on device 100, enhancing comfort, and reducing thetendency of wings 130, 131 to peel off of the skin. The advantageprovided by the combination of the floating rigid body 115 and theadhered wings 130, 131 is illustrated in FIGS. 8A and 8B. In FIG. 8A, apatient is sleeping, and in FIG. 8B, a patient is playing golf. In bothexamples, monitoring device 100 is squeezed together by the patient'sbody, causing housing 115 to float above the skin as wings 130, 131 movecloser together. This advantage of a floating, non-attached portion of aphysiological monitoring device is described in further detail in U.S.Pat. No. 8,560,046, which was previously incorporated by reference.

Referring now to FIGS. 9A-9F, one embodiment of a method for applyingphysiological monitoring device 100 to the skin of a human subject isdescribed. In this embodiment, before the first step shown in FIG. 9A,the patient's skin may be prepared, typically by shaving a small portionof the skin on the left chest where device 100 will be placed and thenabrading and/or cleaning the shaved portion. As shown in FIG. 9A, oncethe patient's skin is prepared, a first step of applying device 100 mayinclude removing one or both of two adhesive covers 600 from adhesivelayers 340 on the bottom surface of device 100, thus exposing adhesivelayers 340. As illustrated in FIG. 9B, the next step may be to applydevice 100 to the skin, such that adhesive layer 340 adheres to the skinin a desired location. In some embodiments, one adhesive cover 600 maybe removed, the uncovered adhesive layer 340 may be applied to the skin,and then the second adhesive cover 600 may be removed, and the secondadhesive layer 340 may be applied to the skin. Alternatively, bothadhesive covers 600 may be removed before applying device 100 to theskin. While adhesive covers 600 are being removed, liner 810 acts as asupport for flexible body 110, provides the physician or other user withsomething to hold onto, and prevents flexible body 110 and borders 133of flexible body 110 from folding in on themselves, forming wrinkles,and so forth. As described above, liner 810 may be made of a relativelystiff, firm material to provide support for flexible body 110 duringapplication of device 100 to the skin. Referring to FIG. 9C, afterdevice 100 has been applied to the skin, pressure may be applied toflexible body 110 to press it down onto the chest to help ensureadherence of device 100 to the skin.

In a next step, referring to FIG. 9D, liner 810 is removed from (forexample, peeled off of) the top surface of flexible body 110. As shownin FIG. 9E, once liner 810 is removed, pressure may again be applied toflexible body 110 to help ensure it is adhered to the skin. Finally, asshown in FIG. 9F, upper housing member 140 may be pressed to turn onphysiological monitoring device 100. This described method is only oneembodiment. In alternative embodiments, one or more steps may be skippedand/or one or more additional steps may be added.

In certain embodiments, when a desired monitoring period has ended, suchas about 14 to 21 days in some cases, a patient (or physician, nurse orthe like) may remove physiological monitoring device 100 from thepatient's skin, place device 100 in a prepaid mailing pouch, and maildevice 100 to a data processing facility. At this facility, device 100may be partially or completely disassembled, PCBA 120 may be removed,and stored physiological data, such as continuous heart rhythminformation, may be downloaded from device 100. The data may then beanalyzed by any suitable method and then provided to a physician in theform of a report. The physician may then discuss the report with thepatient. PCBA 120 and/or other portions of device 100, such as housing115, may be reused in the manufacture of subsequent devices for the sameor other patients. Because device 100 is built up as a combination ofseveral removably coupled parts, various parts may be reused for thesame embodiment or different embodiments of device 100. For example,PCBA 120 may be used first in an adult cardiac rhythm monitor and thenmay be used a second time to construct a monitor for sleep apnea. Thesame PCBA 120 may additionally or alternatively be used with adifferently sized flexible body 110 to construct a pediatric cardiacmonitor. Thus, at least some of the component parts of device 100 may beinterchangeable and reusable.

In further embodiments described in greater detail below, the monitoringdata may be transmitted wirelessly or through other communicationmediums to be analyzed, rather than requiring physical shipment of thedevice for analysis and reporting.

Advantageously, physiological monitoring device 100 may provide longterm adhesion to the skin. The combination of the configuration offlexible and conformal body 110, the watertight, low profileconfiguration of housing 115, and the interface between the two allowsdevice 100 to compensate for stress caused as the skin of the subjectstretches and bends. As a result, device 100 may be worn continuously,without removal, on a patient for as many as 14 to 21 days or more. Insome cases, device 100 may be worn for greater or less time, but 14 to21 days may often be a desirable amount of time for collecting heartrhythm data and/or other physiological signal data from a patient.

One or more of the various components of the physiological monitoringdevice 100 may be alternatively configured or substituted withembodiments of components disclosed elsewhere herein. For example, insome embodiments, the electrodes 350 and/or flexible body 110 may beconfigured to deliver one or more therapeutic drugs to the patient'sskin. The one or more therapeutic agents may be configured to combatskin irritation, itchiness, and/or bacterial growth; may be configuredto induce or block histamine release; and/or may comprise anestheticqualities, any of which may improve patient compliance and/or prolongthe duration of wear of the physiological monitoring device 100. Thetherapeutic agents may serve alternative or additional therapeuticpurposes as well. In some embodiments, the therapeutic agents may beincorporated directly into the adhesive layer 340. For example, thetherapeutic agents may be mixed into a hydrocolloid solution duringfabrication of the adhesive layer 340. The therapeutic agents may beconfigured to elute from the adhesive layer 340 into contact with thepatient's skin. The adhesive layer 340 can be configured to providecontrolled release of the drug. For instance, the adhesive layer 340 maybe configured to release the drug gradually and/or at a substantiallyconstant rate over a period of time (e.g., over about: 1 week, 2 weeks,3 weeks, 4 weeks, 5 weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks,etc.). The adhesive layer 340 may comprise perforations and/or amicroporous structure configured to facilitate diffusion of the one ormore therapeutic agents through the thickness of the adhesive layer 340.In some embodiments, the therapeutic agents may be incorporated into oneor more overlaying support layers of the flexible body 110, such as thetop substrate layer 300 and/or the bottom substrate layer 330. Thesupport layers of the flexible body 110 may comprise pockets orcontainers configured to store the one or more therapeutic agents. Thepockets may be in fluid communication with the adhesive layer 340through perforations formed in the substrate layer or through pores orchannels formed in the substrate layers. In some embodiments, the one ormore therapeutic agents may diffuse through the adhesive layer 340 toreach the skin. In some embodiments, the perforations in the substratelayers may extend through the adhesive layer 340 to the surface of thepatient's skin. In some embodiments, the electrodes 350 or flexible body110 may be configured to include antimicrobial agents to inhibit thegrowth of microorganisms. The agents may include coatings or embeddedingredients in the adhesive or electrode gel materials. Theseantimicrobial agents may be configured for release gradually and/or at asubstantially constant rate over a period of time (e.g., over about: 1day, 3 days, 5 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 1 month, 3 months, 5 months,1 year, 3 years, 5 years, etc.). The adhesive layer 340 may compriseperforations and/or a microporous structure configured to facilitatediffusion of the one or more therapeutic agents through the thickness ofthe adhesive layer 340. Alternately, the antimicrobial properties may beintrinsic to the structure of the adhesive, gels or any substrate orsupport layer. In embodiments, the electrodes 350 or flexible body 110may be configured to release deodorant or perfume components to limitodor arising from long-term wear. Similar to therapeutic andantimicrobial agents described above, the components could be configuredto release over time and/or diffuse through the thickness of theadhesive or gel layers.

FIGS. 10A-10C schematically illustrate alternative examples of tracelayer 609. The trace layer 609 may comprise an electrical trace 611, 612for each electrode 350 (such as shown in FIG. 3B) of the physiologicalmonitoring device 100. The electrical traces 611, 612 may be disposed on(e.g., printed onto) a non-conductive insulating layer 613. In someembodiments, the insulating layer 613 may comprise a polyester, such aspolyethylene terephthalate (PET) and/or another non-conductive polymer.One or more of the electrical traces 611, 612 may be disposed on thesame insulating layer 613. The insulating layer 613 may be configured tomaintain a separation between the electrical traces 611, 612 that arecoupled to distinct electrodes 350. The electrical traces 611, 612 mayextend from the electrodes 350 into the housing 115 to make electricalcontact with the PCBA 120. In some embodiments, such as embodiments inwhich the physiological monitoring device 100 comprises two oppositewings 130, 131 arranged generally collinear with one another, theelectrical traces 611, 612 may extend generally collinearly along adirection defining a longitudinal axis of the device. A transverse axismay be defined substantially perpendicular to the longitudinal axis. Thelongitudinal axis and/or the transverse axis may substantially bisectthe housing 115 of the physiological monitoring device 100.

Each trace 611, 612 may extend from an electrode contact area configuredto contact an electrode 350 along a connecting portion of the tracelayer 609 to a housing area configured to be received within the housing115 (e.g., between an upper housing 140 and a lower housing 145, such asshown above in FIG. 7 and below in FIGS. 12-13B). The housing area ofthe trace layer 609 may have an area generally configured to match theperimeter of the upper housing 140 and lower housing 145 where thehousings meet (or as described below in relation to the embodiments ofFIGS. 12A-15I, such as 640 and 645). For instance, the trace layer 609may comprise a generally circular housing area. The trace layer 609 mayhave a plurality of holes 616 extending between upper and lower surfacesof the trace layer 609. The holes 616 may allow mechanical elements(e.g., posts as described elsewhere herein) to pass through, such asmechanical elements which couple or mate the upper housing 140 and thelower housing 145. The holes 616 may be disposed generally along aperimeter of the housing area of the trace layer 609. The holes 616 mayextend through only the insulating layer 613 and not the electricaltraces 611, 612. At least some of the holes 616 may be configured indimension to substantially match the size of one or more mechanicalmating elements (e.g., posts) such that passage of the one or moremechanical mating elements through the holes 616 may help stabilize theorientation of the trace layer 609 and/or may help secure the tracelayer 609 to the housing 115. The housing area of the trace layer 609may comprise a large central hole through which components in the upperhousing 140 may directly contact components in the lower housing 145 (oras described below in relation to the embodiments of FIGS. 12A-15I, suchas 640 and 645). The housing area of the electrical traces 611, 612 maybe disposed on opposite sides of the insulating layer 613 within thehousing area of the trace layer 609. The trace layer 609 may extendgenerally along the longitudinal axis between the electrode contactareas. The connecting portions of the trace layer 609 between theelectrode contact areas and the housing areas may comprise a width alongthe transverse direction less than that of the electrode contact areasand/or the housing areas of the trace layer 609.

The electrical traces 611, 612 may be disposed (e.g., printed and/orapplied in any suitable manner) on one or both sides (top and bottom) ofthe insulating layer 613. The electrical traces 611, 612 may compriseany of the conductive materials discussed elsewhere herein. Forinstance, in some embodiments, the electrical traces 611, 612 maycomprise a layer of silver (Ag) printed on the insulating layer 613. Inembodiments, the electrode interface portion 310 of the electricaltraces 611, 612 may comprise a layer of silver chloride (AgCl) inaddition to or alternatively to the layer of silver or other conductivematerial generally used for the traces 611, 612, as described elsewhereherein. In some embodiments, the layer of silver chloride or otherelectrode interface material may be printed over the top of the layer ofsilver or other conductive layer of the electrical traces 611, 612.Silver may provide a more isotropic conductance than silver chloride,which may provide better lateral conductance in an x- and y-directionsbut worse vertical conductance along a z-direction (transverse to thelongitudinal and lateral axes). In some embodiments, the electricaltraces 611, 612 may be disposed primarily on one side of the insulatinglayer 613 (e.g., the bottom side or patient-facing side). For instance,the electrode interface portion 310 and portions of the traces 611, 612along the connecting portion of the trace layer 609 may be disposed ononly a single side, but the electrocardiogram circuit interface portion313 of the traces 611, 612 may be positioned on the opposite side of thetrace layer 609. Positioning the electrode interface portion 310 andelectrocardiogram circuit interface portion 313 on opposite sides of thetrace layer 609 may allow for facile interfacing between the electricaltraces 611, 612 and PCBA 120, which may be positioned opposite the tracelayer 609 from the patient's skin to minimize the amount of spaceoccupied by the housing 115 between the patient and the trace layer 609.In certain embodiments, the trace layer 609 may comprise one or morevias 619 formed in through holes of the trace layer 609 that extendthrough the insulating later 613. The through holes may be formedthrough the conductive material electrical traces 611, 612 and filledwith the same and/or a different conductive material to form the vias619 which conduct electric signals from one side of the trace layer 609to the other. The vias 619 may simplify the design and construction ofthe trace layer 609 by avoiding the use of bends in metal components. Insome embodiments, conductive rivets may be used in addition to oralternatively to the conductive vias 619. The electrocardiogram circuitinterface portion 313 of the traces 611, 612 may comprise relativelylarger surface areas than the traces 611, 612 along the connectingportion of the trace layer 609 in order to provide sufficient contactarea for electrical contacts to electrically couple the traces 611, 612to the PCBA 120.

As shown in FIG. 10B, in some embodiments, one or more resistors 614 maybe disposed within the electrical traces 611, 612. The resistors 614 maycomprise a conductive material of increased resistance over theconductive material(s) (e.g., silver and/or silver chloride) used togenerally conduct electricity between the electrodes 350 and the PCBA120. For example, the resistors 614 may comprise carbon and/or increasedamounts of carbon as compared to the electrical traces 611, 612. In someembodiments, the resistors may have a resistance that is at leastapproximately about: 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100kiloohms (kΩ). The material of the resistor 614 may be selected toreduce or minimize “popcorn” noise or 1/f noise. As shown in FIGS.10A-10C, the resistors 614 may intersect the conductive path of theelectrical traces 611, 612 between the electrode interface portion 310and the electrocardiogram interface portion 313 such that they aredisposed in-line with the conductive material of the electrical traces611, 612. The resistors 614 may be disposed on a housing portion of thetrace layer 609 such that they are enclosed within the housing 115. Theresistors 614 may be disposed (e.g., printed) onto the substrate layer613 in the same manner or a different manner from the conductivematerial of the electrical traces 611, 612. The resistors 614 mayreplace resistors that would otherwise be disposed on the PCBA 120,thereby potentially providing space-saving advantages. In someembodiments, the resistors 614 may be used to reduce the current thattravels along the electrical circuit formed by the body and theinterfacing electrodes 350. The resistors 614 may act as a safetyfeature that allows the physiological monitoring device 100 to besuitable for use with a patient.

Returning to FIG. 10A, in some embodiments, the electrode interfaceportions 310 may comprise a central aperture 617. The central aperture617 may be generally circular or any suitable shape, for example anoval, square, triangle, rectangle, or suitable polygonal shape. Thecentral aperture 617 may provide for improved moisture management. Forexample, moisture trapped between the electrode 350 and the skin of thepatient may be able to transpire through the electrode (e.g., a hydrogelelectrode) and evaporate through the central aperture 617 and/ortranspire through breathable substrate layers positioned over centrallayer. Improving moisture management may inhibit delamination andincrease the duration of wear of the physiological monitoring deviceallowing for longer use. In some embodiment, the trace layer 609 maycomprise a plurality of central apertures 617 positioned over the topsurface of the electrode 350. The cumulative surface area of the one ormore central apertures and/or vias 619 may be balanced relative to thesurface area of the electrode 350 to prevent dry-out of hydrogelelectrodes 350 and/or to attenuate fluctuations in conductivity that mayoccur as the electrode delaminates from the skin, since the metal ismore conductive than the hydrogel. In some embodiments, no substratelayers may be positioned over the trace layer 609 or any overlyingsubstrate layers may comprise corresponding apertures positioned overthe central aperture 617 such that at least a portion of the uppersurface of the electrode 350 is exposed to the ambient environment. Insome embodiments, the diameter of the central aperture 617 may besomewhat smaller than an outer diameter of the electrode 350 such thatthe trace layer 609 is seated on top of a top surface of the electrode350. An electrical connection may be formed between an upper surface ofthe electrode and a lower surface of the trace layer 609 via theelectrode interface portion 310 of the electrical trace 611, 612. Insome embodiments, the diameter of the central aperture 617 substantiallymatches the outer diameter of the electrode 350 such that the electrode350 may be received within the central aperture 617. An electricalconnection may be formed between lateral edges of the conductive traces611, 612 and the lateral sides of the electrode 350 in addition oralternatively to interactions between other portions and surfaces. Insome embodiments, the electrode 350 (e.g., a hydrogel electrode or anysuitable electrode) may be formed in situ within the central apertureand/or swelled within the central aperture 617. The electrode 350 may beswelled to have a diameter slightly larger than the diameter of thecentral aperture 617 such that a compressive force induces sufficientcontact between the trace layer 609 and the electrode 350.

FIG. 10A illustrates an example of a trace layer 609. FIG. 10B depicts aclose-up of the inset A in FIG. 10A. As shown in FIG. 10A, theconnecting portions of the trace layer 609 may substantially bisect thehydrogel electrode 350 and/or the electrode interface portion 310 of thetraces 611, 612. The electrical traces 611, 612 may be substantiallylinear along the connecting portion of the trace layer 609 as shown inFIG. 10A. In some embodiments, one or more of the electrical traces 611,612 may comprise a plurality of bends. The plurality of bends mayproduce a zig-zag or accordion-like configuration which allows the oneor more of the electrical traces 611, 612 to better absorb tensileand/or compressive strains along the longitudinal axis. FIG. 10Cillustrates another example of a trace layer 609. The trace layer 609may not be symmetrical about the transverse and/or the longitudinal axisas shown in FIG. 10C. In some embodiments, the electrode interfaceportion 310 of one trace 611 may be configured to be positioned higherup on the patient's body than the electrode interface portion 310 of theother trace 612. The electrode interface portions 310 may extend awayfrom the portion of the traces 611, 612 along the connecting portion ofthe trace layer 609 in lateral directions parallel to the transverseaxis. The electrode interface portions 310 may extend away from theconnecting portions in opposite directions. In some embodiments, theentire trace 611 may be configured to be positioned higher up on thepatient's body than the opposing trace 612 as shown in FIG. 10C. Theconnecting portions of the trace layer 609 may be substantially parallelbut may be offset along the transverse axis such that the connectingportions are not collinear. In some embodiments, both the connectingportions may be offset and the electrode interface portions 310 of thedifferent traces 611, 612 may extend in opposite directions as shown inFIG. 10C. The lateral offsetting of the electrodes 350 along thetransverse axis may be configured to appropriately position theelectrodes as shown in FIGS. 9A-9F while allowing the transverse axis toremain parallel to the height of a patient.

In some embodiments, the electrode interface portions 310 of one or moreof the traces 611, 612 may be configured as a closed loop of the tracelayer 609 which extends 360 degrees to enclose the central aperture 617.The trace layer 609 along the loop may comprise a substantially uniformwidth which may be the same width as the trace layer 609 along theconnecting portion. In certain embodiments, the width may be nonuniform.The electrical trace 611, 612 may extend along the entire circumferenceof the loop or may extend only partially along the loop such that theelectrical trace 611, 612 does not form a closed loop with itself.

In some embodiments, the physiological monitoring device 100 maycomprise a battery terminal connector 650 configured to physicallyconnect the two opposite terminals of a battery. FIGS. 11A-11Eschematically depict two examples of a battery terminal connector 650.FIG. 11B depicts an inner surface of a battery terminal connector 650configured to contact the battery terminals and FIG. 11A depicts anouter surface of the battery terminal connector 650 opposite the surfacedepicted in FIG. 11B. FIG. 11D depicts an inner surface of anotherexample of a battery terminal connector 650 configured to contact thebattery terminals and FIG. 11C depicts an outer surface of the batteryterminal connector 650 opposite the surface depicted in FIG. 11D. FIG.11E illustrates a side view of a battery 160 to which a battery terminalconnector 650 has been coupled (e.g., adhered). The battery terminalconnector 650 may be configured to electrically connect to each of theterminals of a battery 160 and to functionally reposition electricalaccess to the battery terminals. The battery terminal connector 650 maybe configured to connect the terminals of a coin-style battery or abattery comprising opposing top and bottom sides in which one terminalis positioned on the top side and the opposite terminal is positioned onthe bottom side. In certain embodiments, the battery terminal connector650 may be configured to position electrical access to both terminals ofthe battery on a single side of the battery (e.g., the top side) inorder to simplify the electrical coupling of each terminal to the PCBA120. Accordingly, the battery terminal connector 650 may comprise afirst portion 655 (e.g., a bottom portion), a top portion 657 (e.g., atop portion), and a connecting portion 656 joining the first portion 655and the second portion 657. At least the connecting portion 656 of thebattery terminal connector 650 may be sufficiently flexible such thatthe connecting portion 656 may bend, fold, or wrap around a lateral sideof the battery 160 between top and bottom surfaces of the battery 160.

The battery terminal connector 650 may comprise an insulating layer 651and two conductive battery traces 652, 653. Each of the battery traces652, 653 may be configured to contact one of the two battery terminals.The insulating layer 651 may be configured to maintain a separationbetween the two battery traces 652, 653, thereby insulating the batterytraces 652, 653 from one another. The insulating layer 651 may beconfigured to prevent at least one of the battery traces 652, 653 fromcontacting the battery terminal electrically coupled to the otherbattery trace. The insulating layer 651 may be formed of anon-conductive material. For instance, the insulating layer 651 maycomprise a polyethylene such as polyethylene terephthalate (PET) orother suitable non-conductive polymers. The battery traces 652, 653 maybe formed of a highly conductive material configured to electronicallyconnect the battery terminals to the circuitry of the physiologicalmonitoring device 100. For instance, the battery traces 652, 653 maycomprise silver or copper (e.g., tin-plated copper foil). At leastportions of the inner surface of the battery terminal connector 650 maybe adhered to the battery terminals using a conductive adhesive (e.g., aconductive acrylic adhesive) configured to electrically couple each ofthe battery terminals to one of the battery traces 652, 653.

The battery terminal connector 650 may comprise any suitable arrangementof the battery traces 652, 653 and the insulating layer 651. In variousembodiments, one of the battery traces 652 may extend from a first sideof the battery (e.g., a bottom side) to the second side of the battery(e.g., the top side). The first battery trace 652 may be exposed on theinner surface of the battery terminal connector 650 on the first side ofthe battery 160 and exposed on only the outer surface of the batteryterminal connector 650 on the second side of the battery 160. The secondbattery trace 653 may be disposed on only the second side of the battery160. The second battery trace 653 may be exposed on both the innersurface and the outer surface of the battery terminal connector 650 onthe second side of the battery 160. The PCBA 120 may be configured toform electrical contacts with both of the battery traces 652, 653 on theouter surface of the battery terminal connector 650 as describedelsewhere herein. The insulating layer 651 may be disposed on at leastthe second side of the battery 160 to separate the battery traces 652,653 on the second side of the battery 160 and to insulate the firstbattery trace 652 from the battery terminal on the second side of thebattery 160. In embodiments, the insulating layer 651 may be disposed onthe inner surface of the battery terminal connector 650 along theconnecting portion 656 and/or along at least portions of the first sideof the battery 160 (e.g., the bottom portion). The insulating layer 651may be disposed on the outer surface of the battery terminal connector650 along the connecting portion 656 and/or the first side of thebattery 160 (e.g., the bottom portion).

Returning to FIGS. 11A-11B, in some embodiments, the second batterytrace 653 may be disposed (e.g., printed or via other suitable means) onthe outer surface of the battery terminal connector 650 but may comprisean extension 654 extending beyond an edge of the insulating layer 651such that the battery terminal on the second side of the battery 160 mayelectrically contact the extension 654 of the second battery trace 653and the electric current may be transferred to the outer surface of thebattery terminal connector 650 via the extension 654. In someembodiments, as shown in FIGS. 11C-11D, the second battery trace 653 maybe disposed (e.g., printed) on the inner surface and the outer surfaceof the battery terminal connector 650. The second battery trace 653 maysandwich a portion of the insulating layer 651. The battery terminalconnector 650 may comprise through holes filled with conductive materialto form vias electrically connecting the second battery trace 653 on theinner surface and the outer surface of the battery terminal connectorsuch that electrical current may be transferred from the second side ofthe battery though the battery terminal connector 650 to an outersurface of the battery terminal connector 650. In some embodiments, viasmay also electrically connect the first battery trace 652 between aninner surface and an outer surface of the battery terminal connector650. Conductive rivets may be used in addition to or alternatively tothe conductive vias disclosed herein. FIGS. 11F through 11I depict anexample of a battery terminal connector 650 configured to contact thebattery terminals. FIG. 11F depicts the outer surface of the batteryterminal connector 650 prior to application of non-conductive coverlayand/or layer 658 (as shown in FIG. 11H), while FIG. 11G depicts theinner surface of the battery terminal connector 650 prior to addition ofadhesive 660 (as shown in FIG. 11I). In some embodiments, a secondnon-conductive layer 658 may cover the first battery trace 652 and theconnecting portion 656 on the outside surface of the battery terminalconnector 650. In certain embodiments, the battery terminal connector650 may have at least one protruding tab 659 to positionally fix thebattery terminal connector and battery assembly inside of the devicehousing. There may be one, two, three, four, or more protruding tabs.One of skill in the art will understand that the protruding tabs may beshaped in any suitable manner, such as a curved shape or an angularshape.

FIGS. 12A-12G illustrate multi-perspective views of another example ofan upper housing 640. FIG. 12A depicts a partially exploded view of theupper housing 640. In some embodiments, the upper housing 640 may have acircular, ovoid, obround, rectangular, square, or any other suitableprofile shape in the horizontal plane. The upper housing 640 maycomprise a flexible upper frame 642 and a rigid shell 643. FIG. 12Bshows a perspective view of the flexible upper frame 642. FIG. 12C showsa side view of the flexible upper frame 642. FIG. 12D shows a top viewof the flexible upper frame 642. The rigid shell 643 may be more rigidthan the flexible upper frame 642. For example, the rigid shell 643 maybe formed from a hard plastic (e.g., a polycarbonate such as Makrolon™)and the flexible upper frame 642 may be formed from a softer rubber(e.g., Santoprene™). The upper housing 640 may comprise a button 644forming at least a portion of a top surface of the upper housing 640 andenclosing the internal components of the housing 615 from above. Thebutton 644 may be a separate piece that is assembled with the flexibleupper frame 642 and rigid shell 643 to form the upper housing 640, asshown in FIG. 12A. The button 644 may be relatively rigid relative tothe flexible upper frame 642. In some embodiments, the button 644 may beformed from the same material as the rigid shell 643. The button 644 maybe securely attached to the flexible upper frame 642 by any suitablemeans (e.g., using adhesive, detents, snap fits, etc.) such that thebutton 644 is configured as “floating” button over the internal space ofthe upper housing 640. In some embodiments, the flexible upper frame 642may be overmolded over at least a portion of the upper and lowersurfaces of the button 644. Overmolding may be used to secure the button644 to the rigid shell 643. In some embodiments, the button 644 may beentirely encased within the flexible upper frame 642.

The rigid shell 643 may form a lateral surface of the upper housing 640(e.g., a circumference), as shown in FIG. 12A. The rigid shell 643 mayform an outer annular portion or an outer perimeter of a top surface ofthe upper housing 640, as shown in FIG. 12A. The flexible upper frame642 may be overmolded to the rigid shell 643. The flexible upper frame642 may join the rigid shell 643 to the button 644 as describedelsewhere herein. The flexible upper frame 642 may fill an annular gapin a top surface of the upper housing 640 between the outer perimeterformed by the rigid shell 643 and the button 644 forming a flexibleborder to the button 644. The flexible upper frame 642 may be configuredto be biased in a manner that allows the button 644 to be depressed in adownward direction relative to the rigid shell 643 to actuate trigger210. In some embodiments, the lower surface of the button 644 may beshaped to have a convex surface or other protrusion configured toactuate the trigger input 210. In some embodiments, a protrusion (e.g.,an upside-down dome, pillar, or any suitable shape) may be attached to alower surface of the button 644. The protrusion may accentuate thetrigger actuation such that less strain is required to actuate thetrigger input 210. The protrusion may be made of metal and/or plastic.

In some embodiments, the button 644 may be configured as a cantileverbutton rather than a floating button, in which a cantilever arm connectsthe button 644 to a lateral side (e.g., an inner diameter) of the rigidshell 643. The cantilever arm may be concealed by the flexible upperframe 642 such that the button 644 nonetheless externally appears as afloating button. In some embodiments, the button 644 may not be afloating button but may be integral with or directly joined to the rigidshell 643. The button 644 may be semi-rigid but comprise sufficientflexibility such that the button 644 can be elastically deformed. Thebutton 644 may comprise a raised and/or convex configuration (e.g., adome-like configuration) when unbiased. The button 644 may be configuredsuch that the shape of the button 644 can be elastically deformed toactuate the trigger input 210. For instance, a dome may be at leastpartially inverted at or near an apex of the dome, such that the centerof the domed button 644 extends downward within the space enclosed bythe upper housing 640 to actuate the trigger input 210. In someembodiments, upon reaching a threshold strain, the dome may snap orbuckle into an inverted configuration in which less pressure is requiredto continue depressing the dome. The buckling or snapping effect may beconfigured to provide a useful tactile indication of trigger 210actuation. In some embodiments, upon release of pressure, the dome maysnap back to its unbiased configuration. In some embodiments, the domedbutton 644 may include a conductive material or be coated in aconductive surface, and the domed body may make direct contact withelectrical terminals on the PCBA 120 to actuate a trigger input withoutneed for an additional trigger input button 210 on the PCBA. In certainembodiments, the button 644 may be rigid, but is attached to anelastically deformable snap dome that makes contact direct contact withelectrical terminals on the PCBA 120 while providing tactile feedback tothe user. In some embodiments, the semi-rigid button 644 may be snappedinto the rigid shell 643 such as through a lip seal (the button 644 maybe attached over an o-ring). In some embodiments, the button 644 may beultrasonically welded or sealed onto the rigid shell 643. In someembodiments, the button 644 may be formed as a thinned-out portion ofthe upper surface of the rigid shell 643. In some embodiments, thebutton 644 may be formed from a soft material, such as a thermoplasticelastomer, configured to fold, flex, and/or rebound. The button 644 maycomprise a hard external surface piece mounted onto the softer materialfor the user to press and/or a hard internal surface piece mounted ontothe softer material for contacting the trigger input 210. In someembodiments, the softer material for contacting the trigger input mayinclude a soft conductive piece (such as a conductive foam pill)enabling trigger input by shorting pads or traces on the PCBA withoutrequiring an explicit button component on the PCBA. In some embodiments,the button 644 may be configured similarly to a computer keyboardbutton. For instance, the button 644 may be configured to sit on one ormore support members that surround the trigger input 210 and hold thebutton 644 over the trigger input 210 in a biased non-contactingposition. In some embodiments, the electrical signal indicating buttondepression may be depressed through to the printed circuit board,through a flex circuit attached to the button or through electricaltraces applied to the rigid shell 643. These electrical traces may beapplied via laser direct structuring, plating to a palatable substrateapplied in a secondary mold process, or printing via aerosol jet, inkjetor screen printing of conductive materials.

The flexible upper frame 642 may comprise an upper rim 642 a configuredto interface with the top surface of the rigid shell 643, as describedelsewhere herein, and a lower rim 642 b. The lower rim 642 b maycomprise a larger diameter than the upper rim 642 a. The upper rim 642 aand/or the lower rim 642 b may comprise annular (e.g., ring-shaped)configurations. The lower rim 642 b may be configured to interface withthe lower surface of the lateral sidewall of the rigid shell 643 (e.g.,via overmolding or a snap fit). An inner diameter of the lower rim 642 bmay be configured to interface with an outer diameter of the PCBA 120(e.g., via a snap fit). The lower rim 642 b may functionally couple thePCBA 120 to the rigid shell 643. In some embodiments, the lower rim 642b may be approximately the same rigidity as the upper rim 642 a. In someembodiments, the lower rim 642 b may be more rigid than the upper rim642 a. The upper rim 642 a may be joined to the lower rim 642 b by oneor more vertical ribs 642 c. A plurality of ribs 642 c may be spaced(e.g., substantially uniformly) around the periphery of the upperhousing 640. The ribs 642 c may help retain the PCBA 120 within theupper housing. In some embodiments, the PCBA 120 may be configured withgrooves in the peripheral edge of the PCBA 120 to at least partiallyreceive one or more of the ribs 642 c. The ribs 642 c may at leastpartially conform to the shape of the PCBA 120. The ribs 642 c may helpabsorb shock that would otherwise be transmitted to the PCBA 120 andcould, for instance, potentially cause motion artifacts. Some of theribs 642 c may not join the upper rim 642 a and the lower rim 642 b.Some of the ribs 642 c may extend upward from the bottom rim 642 b butdo not attach to the upper rim 642 a, as shown in FIGS. 12B-12D. Some ofthe ribs 642 c may extend downward from the upper rim 642 a but do notattach to the lower rim 642 b. In some embodiments, only a single rib642 c connects the upper rim 642 a and the lower rim 642 b, as shown inFIGS. 12B-12D. In some embodiments, the upper rim may not connect to thelower rim, or one of the two rings may be omitted entirely.

In some embodiments, one or more connecting ribs 642 c may becircumferentially positioned substantially opposite the trigger input210. The one or more connecting ribs and/or frames 642 may act as afulcrum or pivot point about which the upper rim 642 a and the button644 are depressed. The fulcrum-like arrangement may allow deeperdepression of the button 644 on the side of the PCBA 120 comprising thetrigger input 210. In some embodiments, one or more fulcrum posts mayextend upward (e.g., from the PCBA 120) vertically beneath the button644. The fulcrum posts may be spaced around a periphery beneath thelower surface of the button 644. The fulcrum posts may have a heightshorter than that of the trigger input 210. The fulcrum posts may act asfulcrums and facilitate biasing the lower surface of the button 644toward the trigger input 210 as the button 644 is depressed if the lowersurface of the button 644 contacts the fulcrum post. The fulcrum postsmay be particularly useful if the trigger input is positioned off-centerof the button 644 (e.g., on a periphery of the PCBA 120). In someembodiments, the upper rim 642 a of the flexible upper frame 642 may befilled to form a continuous area such that the upper frame 642 maycomprise an upper surface flush with the upper surface of the rigidshell 643 and covering a central portion of the top surface of the upperhousing 640. In some embodiments, the button 644 may be formed as anintegral portion of the flexible upper frame 642 and may beapproximately the same or even less rigid as the remainder of theflexible upper frame 642. In some embodiments, a button 644 (which maybe flexible or rigid) may be coupled to an upper surface of the flexibleupper frame 644 (e.g., underneath the upper surface). The button 644 maybe attached to the upper surface of the upper frame 642 (which may beflexible or rigid) via a snap-fit, barb-fit, adhesive, suction force,etc. In some embodiments, in order to minimize the potential for PCBAflex during application of force on the input trigger by the button, theupper housing 640 may include a stop feature that limits the travel ofthe button 644 to minimize stress to the board. Such a stop featurecould also be implemented as a component on the PCBA, for example as anon-active molded component that is press-fit on the PCBA or an activecomponent such as an antenna that is soldered to the board but has adeliberate extension to enable limiting the button's travel.

FIG. 12E depicts a perspective view of an inner surface of the upperhousing 640. In some embodiments, the upper housing 640 may comprisedownward extending columns 641 configured for securing or helping tosecure the upper housing 640 to a lower housing 645. The columns 641 maybe spaced (e.g., substantially uniformly) around a periphery of theupper housing 640. The columns 641 may have channels configured toreceive and retain posts 646 extending from a lower housing 645 asdescribed elsewhere herein (e.g., via a press fit or an interferencefit). The columns 641 may be formed as part of the rigid shell 643. Thecolumns 641 may be formed integrally with the rigid shell 643. Thecolumns 641 may be positioned inward of the lower rim 642 b of theflexible upper frame and/or housing 640. One or more of the columns 641may be merged together with an inner diameter of the rigid shell 643, asshown in FIG. 12E. One or more of the columns 641 may be spaced inwardfrom the inner diameter of the rigid shell 643. The columns 641 mayextend to a height above that of the inner diameter of the upper housing640 as shown in FIG. 12E, to approximately the same height of the innerdiameter of the upper housing 640, or below the height of the innerdiameter of the upper housing 640. The flexible upper frame 642 mayextend to a height above that of the inner diameter of the rigid shell643, to approximately the same height of the inner diameter of the rigidshell 643, or below the height of the inner diameter of the rigid shell643 as shown in FIG. 12E. In certain embodiments, and as describedabove, button 644 may flex as an integrated part of the housing and/orshell 643. In such an embodiment, upper rim 642 a is no longernecessary. A window may be added to button 644 covered in a thin layerof semi-transparent material to allow for light transmission from anunderlying LED.

As shown in FIG. 12F, top 714 and bottom 716 portions of the housing maybe positioned above and below the flexible body 718. As shown in FIG.6D2, in embodiments, a gasket 719 may be positioned between the upperhousing 714 and lower housing 716, co-molded into one or more of thehousings. The gasket may compress down on the adhesive assembly and aridged interface (shown below in FIG. 12G) or another gasket on theopposite housing to provide waterproofing to the internal electronicshardware. As depicted in FIG. 12G, a ridge 721 may be positioned on anupper edge of the lower housing 716, the ridge 721 configured to pressinto the adhesive layer and/or the gasket 719. One of skill in the artwill understand that the ridge 721 may be of any suitable shape, forexample such as an edged ridge as depicted in FIG. 721. In someexamples, the ridge may be rounded, square, and/or polygonal. In certainexamples, the height of the ridge may be about 0.01 mm to 0.5 mm, about0.05 mm to 0.4 mm, about 0.1 mm to 0.3 mm, about 0.1 mm to 0.2 mm, orabout 0.15 mm such as about 0.13 mm.

FIGS. 13A-13B illustrate multi-perspective views of another example of alower housing 645. The lower housing 645 may be configured to engageupper housing 640. FIG. 13A depicts a perspective view of the lowerhousing 645 and FIG. 13B depicts a side view of the lower housing 645.In some embodiments, the lower housing 645 may comprise a plurality ofposts 646 extending upward from the main body of the lower housing 645beyond an upper peripheral edge configured to meet a lower peripheraledge of the upper housing 640. The posts 646 may be configured to extendinto the internal space enclosed by the upper housing 640. In someembodiments, the posts 646 may not extend beyond the upper peripheraledge of the lower housing 645. In some embodiments, the posts 646 may beconfigured to pass through the holes 616 in the trace layer 609 and mayhelp secure the trace layer 609 to the lower housing 645 as describedelsewhere herein. The plurality of posts 646 may be configured to bereceived within and to mate with an equal number of columns 641positioned opposite the posts 646 in the upper housing 640. For example,the plurality of posts 646 may be configured to form a press-fit or aninterference fit with the plurality of columns 641 such that the posts646 and columns 641 are configured to secure or lock together the upperhousing 640 and the lower housing 645. The engagement between the posts646 and columns 641 may resist separation forces between the upperhousing 640 and the lower housing 645. Separation forces may be inducedby the spring 665 described elsewhere herein, counterforces fromcompression of gaskets between the upper and lower housings 640, 645 toform a watertight seal, the transference of force from the upper housing640 to the lower housing 645 during actuation of the trigger 210, etc.In some embodiments, some or all of the posts 646 may be arranged on theupper housing 640 and some or all of the columns 641 may be arranged onthe lower housing 645. In some embodiments, the lower housing 645 maycomprise one or more buckle columns configured to contact a bottomsurface of the PCBA 120 (or a spring contact spacer as describedelsewhere herein). The buckle columns may be configured to trap the PCBA120 in firm contact against the upper housing 640, subsume the tolerancein the PCBA 120 thickness, and/or provide additional rigidity forinducing a firm tactile response against the button 644 pressing forces.In some embodiments, the lower housing 645 may be joined with the upperhousing 645 through alternate processes, such as ultrasonic welding,potentially removing the need for press fit posts.

In some embodiments, the housing 115 may comprise a spring 665configured to provide a consistent force bias the internal componentsenclosed by the housing 115 into contact with each other. The spring 665may generally bias the components toward the top and/or the bottom ofthe housing 115. The spring 665 may absorb the tolerance stack of theinternal components and maintain a substantially consistent biasing andvertical positioning or spacing between the components regardless ofminor variations in the size of the various internal components or fitwith respect to each other. The spring 665 may bias the PCBA 120 intocontact with hard stops formed in the upper housing 640 such that thePCBA is able to provide a counterforce to resist the button pressingforce and allow actuation of the input trigger 210. In some embodiments,the spring 665 may be a wave spring although other configurations ofsprings (e.g., a coil spring) may be used. In some embodiments, thespring 665 may be replaced by an elastomeric foam which may providedampening properties in addition to the abovementioned properties. FIGS.14A-14B illustrate orthogonal side views of an example of a wave spring665. The wave spring 665 may be configured to be seated substantiallyalong the internal diameter of the housing 115. In some embodiments, thespring 665 may be configured to be seated in the bottom of the lowerhousing 145 and to bias the internal components upward toward the upperhousing 140, as described elsewhere herein.

FIGS. 15A-15I illustrate multiple views of another example of aphysiological monitoring device 600. The physiological monitoring device600 may comprise one or more of the components described elsewhereherein. The physiological monitoring device 600 may comprise a housing615 comprising an upper housing 640 and a lower housing 645 which areconfigured to mate together sandwiching a flexible body 610 between theupper housing 640 and the lower housing 645. The flexible body 610 maycomprise the trace layer 609 and one or more substrate layers formingthe wings of the physiological monitoring device 600. The wings maycomprise adhesive layers 340 and electrodes 350 as described elsewhereherein. The rigid body and/or housing 615 may enclose a PCBA 120, aflexible upper frame 642, a battery 160, a battery terminal connector650, a portion of the trace layer 609, a spring contact spacer 632, anda spring 665.

FIG. 15A depicts a perspective view of an embodiment of thephysiological monitoring device 600. FIG. 15B depicts an exploded viewof the physiological monitoring device 600. FIG. 15C depicts a side viewof the housing 615 in which the rigid shell 643 and button 644 of theupper housing 640 has been removed. FIG. 15D depicts a side view of thehousing 615 as shown in FIG. 15C with flexible upper frame 642additionally being removed. FIG. 15E depicts a side view of the housing615 as shown in FIG. 15D with the lower housing 645 additionally beingremoved. FIG. 15F depicts a side view of the housing 615 as shown inFIG. 15E with the battery 160 and spring 665 additionally being removed.FIG. 15G depicts a sectional view of the housing as shown in Figure withthe section taken between the circuit board 120 and the spring contactspacer 632. FIG. 15H depicts a sectional view of the housing as shown inFIG. 15G with the spring contact spacer 632 additionally being removed.FIG. 15I depicts a side view of the housing 615 as shown in FIG. 15Hadditionally including the PCBA 120.

The upper housing 640 and the lower housing 645 may sandwich theflexible body 610 as described elsewhere herein. In some embodiments,the flexible body 610 may comprise one or more apertures 332 throughextending through one or more of the substrate layers to providebreathability and moisture management and/or to facilitate drug deliveryto the skin of the surface, as described elsewhere herein. An uppergasket layers 360 and/or a lower gasket layer 370 (not shown) may beprovided on opposite sides of the flexible body 610 (not shown). Thegasket layers 360, 370 may be adhesive for adhering to the flexible body610. A compressible seal may be formed above and/or below the flexiblebody 610. In some implementations, a compressive seal may be formed withthe flexible upper frame 642. The battery 160 may be positioned belowthe flexible body 610 comprising the trace layer 609. The PCBA 120 maybe positioned above the flexible body 610 comprising the trace layer609. A battery terminal connector 650 may be adhered or otherwisecoupled to the battery 160 such that first and second battery traces652, 653 are exposed on an outer surface of the battery terminalconnector 650 on a top side of the battery 160. The first and secondbattery traces 652, 653 may be exposed to the internal volume of theupper housing 640 through a large central opening in the housing area ofthe trace layer 609 as shown in FIG. 15H.

Electrical contact between the PCBA 120 and the first and second batterytraces 652, 653 and/or electrical contact between the PCBA 120 and theelectrocardiogram interface portions 313 of the electrical traces 611,612 may be established by spring contacts 637, depicted in FIGS.15G-15I. The spring contacts 637 may be coupled to the bottom surface ofthe PCBA 120 as seen in FIG. 15I. The housing 615 may comprise a springcontact spacer 632 positioned below the PCBA 120 (not shown in FIG.15I). In some embodiments, the spring contact spacer 632 may be rigidlyaffixed (e.g., adhered) to the bottom of the PCBA 120. In embodiments,the spring contact spacer may be attached or integrated into theflexible body 610. In some embodiments, the spring contact spacer may beintegrated into the battery terminal connector. The spring contactspacer 632 may comprise a flat body and a plurality of downwardextending legs 633. The legs 633 may be configured to be seated againsta top surface and/or a lateral surface of the battery 160, as shown inFIG. 15E, such that the spring contact spacer 632 maintains a minimumseparation distance between the battery 160 and the PCBA 120 andprovides sufficient space for the spring contacts 637. The springcontact spacer 632 may comprise one or more holes 634 through which thespring contacts 637 may extend downward from the bottom surface of thePCBA 120, as depicted in FIG. 15G. The lower housing 645 may comprise aspring 665, as described elsewhere herein positioned below the battery160 as shown in FIG. 15E. The spring 665 may bias the battery 160 upwardand may bias the first and second battery traces 652, 653 into physicaland electrical contact with corresponding spring contacts 637. Theelectrocardiogram interface portions 313 of the traces 611, 612 may beseated on a top side of the battery 160 such that biasing the battery160 upward also biases the electrocardiogram interface portions 313 ofthe traces 611, 612 into physical and electrical contact withcorresponding spring contacts 637. The substantially consistent spacingbetween the traces and the PCBA 120 provided by the spring 665 and thespring contact spacer 632 may reduce, minimize, or eliminate noise inthe electrical signal caused by fluctuating degrees of electricalcontact between the spring contacts 637 and the traces. The assembly maycomprise at least one spring contact 637 for each of the first batterytrace 652, second battery trace 653, first electrical trace 611, andsecond electrical trace 612. The assembly may comprise more than onespring contacts 637 for some or all of the traces. The spring contacts637 may be configured under compression induced by the arrangement ofthe various components, including spring 665, to establish an electricalpathway between each of the traces and the PCBA 120. The compressivecontact between the spring contacts 637 and the traces may be maintainedeven under nominal changes in the separation distances between thetraces and the PCBA 120 (e.g., caused by movement) since the springcontacts 637 may extend further downward if the separation distanceincreases and the biasing corresponding decreases. In some embodiments,the first and second battery traces 652, 653 may be configured to bepositioned on an opposite side of the housing 615 from the first andsecond electrical traces 611, 612 as shown in FIG. 15H. In someembodiments, the spring contacts may be configured to carry electricalsignals from battery or electrocardiogram signals by contactingelectrical traces applied to the upper housing 640 or the bottom housing645. These electrical traces may be applied to the housings through theuse of laser direct structuring, plating to a palatable substrateapplied in a secondary mold process, or printing via aerosol jet, inkjetor screen printing of conductive materials. In some embodiments, RFantennas for wireless communication (such as Bluetooth) could beconfigured through the use of such electrical traces in the top housing640 or bottom housing 645.

FIGS. 16A-16D depict multiple views of an embodiment of a physiologicalmonitoring device 800, similar to the physiological monitoring devicesdepicted in FIGS. 10A-15I, such as FIG. 15A. Here, the physiologicalmonitoring device includes a central housing 802, comprising an upperhousing 802 and a lower housing 806 sandwiched over flexible substrate810. One of skill in the art will understand that the housing may beconstructed from any suitable material disclosed herein, such as a rigidpolymer or a soft, flexible polymer. In some embodiments, the housingmay include an indicator 808, which may be in any suitable shape such asan oval, a circle, a square, or a rectangle. The indicator may comprisean LED light source (not shown) or any suitable light source, which maybe overlain by a transparent or translucent viewing layer positionedagainst the inner surface of the upper housing. The viewing layer may beconstructed from thermoplastic polyurethane or any suitable material.The indicator may be used to indicate a status of the physiologicalmonitoring device such as the battery life of the physiologicalmonitoring device. In some embodiments, the indicator may indicatewhether the physiological monitoring device is collecting data,transmitting data, paused, experiencing an error, or analyzing data. Theindicator may display any suitable color, for example red, amber, orgreen.

Extending outward from the housing are a plurality of wings 812. One ofskill in the art will understand that although two wings are depictedhere, some embodiments of the physiological monitoring device 800 mayinclude more than two wings. As explained elsewhere in thespecification, the wings may be shaped in such a way to improve adhesionto the skin and retention of the physiological monitoring device againstthe skin. In embodiments, the wings may asymmetric, with a greaterportion of one wing (an upper lobe) 814 lying above the longitudinalline and a greater portion of another wing lying (a lower lobe) 816below the longitudinal line, thereby allowing the physiologicalmonitoring device to be positioned diagonally over the heart such thatthe lower lobe is positioned lower than the heart when a patient is in astanding position.

Extending outward from the housing and contained on or within the wingsare electrode traces 818, similar to the electrode traces describedelsewhere in the specification, such as with respect to FIGS. 10A-10Cand FIG. 15A. As explained elsewhere in the specification, the electrodetraces may be printed directly on a flexible substrate which may be partof a multi-layer flexible assembly 820. Additional printed lines 822 maysurround the electrode trace 818 for visual enhancement of thephysiological monitoring device, however said printed lines 822 may beprinted on a different layer than the flexible substrate on which theelectrode traces are printed. The printed lines may be printed such thatthey blend with the shape of the electrode trace. As explained elsewherein the specification, the electrode trace may encircle a series ofbreathing holes 824 which allow for air passage to an underlyinghydrogel. In embodiments, there may be one, two, three, four, or morebreathing holes. As explained elsewhere in the specification, apertures826 may extend through one or more layers of the physiologicalmonitoring device to provide breathability and moisture management. Inembodiments, an adhesive border layer 828 may extend outward from thewings, thereby allowing for improved adhesion. FIG. 16B depicts theunderside of the physiological monitoring device 800 depicted in FIG.16A. Here, lower housing 806 is clearly visible as are the electrodetraces 818 and printed lines 822 extending outward from the housing.FIGS. 16C and 16D depict the physiological monitoring device 800 ofFIGS. 16A-16B, here including an externally facing top liner 826 andskin facing patient release liner 828 overlying the wings andsurrounding the housing 802. Such release liners serve to protect thephysiological monitoring device 800 during storage, in particular toprotect the adhesive surfaces of the physiological monitoring device. Inembodiments, the liners may be shaped such that two sides meet to forman opening for the housing to extend vertically past the liners.

In some implementations, an abrader may be used to abrade the skin ofthe patient prior to adhesion of the physiological monitoring device100, 600, 800 (such as described elsewhere in the specification) to thepatient. The abrader may be used to remove a top layer of skin from thepatient to improve long-term adhesion of the physiological monitoringdevice 100, 600 and/or signal quality form the physiological monitoringdevice 100, 600. FIGS. 17A and 17B schematically illustratecross-sectional views of two examples of an abrader 700. The abrader 700may comprise a housing 702. The housing 702 may serve as a handle bywhich the patient or another person can hold and operate the abrader700. In some embodiments, additional elements, such as an elongatedhandle for example, may extend from or otherwise be coupled to thehousing 702. The abrader 700 may comprise a substantially flat abradingsurface 704 for abrading the skin. The abrading surface 704 may comprisea generally large surface area. The abrading surface 704 may comprise arough surface and/or protrusions for abrading the skin. In someembodiments, the housing 702 may entirely or substantiallycircumferentially surround the abrading surface 704, as depicted inFIGS. 17A and 17B. The housing 702 may substantially enclose theabrading surface 704 during the abrasion procedure. The abrading surface704 may be coupled to the housing 702 via a compressible member orbiasing element 706. In some embodiments, the compressible member 706may be a spring as shown in FIG. 17A. In some embodiments, thecompressible member 706 may be a compressible foam as depicted in FIG.17B. The abrading surface 704 may be configured to protrude beyond abottom surface of the housing 702 in an unbiased configuration.

The amount of abrasion may depend on the amount of pressure applied tothe abrader 700. Higher degrees of pressure may result in increasedfriction between the abrader 700 and the skin of the patient resultingin more severe abrasion. Too much pressure may result in patientdiscomfort or pain during and/or after the abrasion procedure. Toolittle pressure may result in inadequate abrasion. The compressibleelement 706 may help the user tune the amount of pressure that isapplied to the abrader 700. The abrader 700 may be configured such thatexertion of a pressure beyond a threshold of necessary pressuresufficiently biases the compressible element 706 to an extent such thatthe abrasion surface is withdrawn into the housing 702 and can no longercontact the skin. In some embodiments, the abrader 700 may be finelytuned such that when the bottom of the housing 702 is pressed intocontact with the skin it deforms the skin encircled by the housing 702to an extent that the abrading surface 704 is still able to make contactwith the skin. The compressible element 706 may provide a tuned amountof force at this level of compression to achieve a desirable degree ofabrasion. In some implementations, a desirable amount of abrasion may beachieved when the abrading surface 704 is fully protruding from thehousing 702 such that the housing does not come into substantial contactwith the skin. In some embodiments, an indicator can be used to indicateto the user that a desired (e.g., a sufficient) amount of pressure hasbeen achieved. For example, the foam compressible member 706 may beformed from an open-cell foam having an internal color and an externalcolor, distinct from the internal color. The foam may be configured tobe visible to the user. For instance, the housing may comprise anannular configuration surrounding the foam compressible member 706 suchthat the foam compressible member 706 is visible from the top during theabrasion procedure, as depicted in FIG. 17B. The internal color of thefoam may be visible when the compressible member 706 is in an unbiasedconfiguration. The compressible member 706 may be configured such thatupon achieving a threshold degree of compression, the open cells arecompressed or closed sufficiently enough that the internal color becomesno longer visible to the user. The color change in the foam may serve asa visual indicator the user that sufficient pressure has been achieved.The visibility of the internal color may indicate to the user that he orshe should exert more pressure.

In various alternative embodiments, the shape of a particularphysiological monitoring device may vary. The shape, footprint,perimeter or boundary of the device may be circular, an oval,triangular, a compound curve or the like, for example. In someembodiments, the compound curve may include one or more concave curvesand one or more convex curves. The convex shapes may be separated by aconcave portion. The concave portion may be between the convex portionon the housing and the convex portion on the electrodes. In someembodiments, the concave portion may correspond at least partially witha hinge, hinge region or area of reduced thickness between the body anda wing.

While described in the context of a heart monitor, the deviceimprovements described herein are not so limited. The improvementsdescribed in this application may be applied to any of a wide variety ofphysiological data monitoring, recording and/or transmitting devices.The improved adhesion design features may also be applied to devicesuseful in the electronically controlled and/or time released delivery ofpharmacological agents or blood testing, such as glucose monitors orother blood testing devices. As such, the description, characteristicsand functionality of the components described herein may be modified asneeded to include the specific components of a particular applicationsuch as electronics, antenna, power supplies or charging connections,data ports or connections for down loading or off-loading informationfrom the device, adding or offloading fluids from the device, monitoringor sensing elements such as electrodes, probes or sensors or any othercomponent or components needed in the device specific function. Inaddition, or alternatively, devices described herein may be used todetect, record, or transmit signals or information related to signalsgenerated by a body including but not limited to one or more of ECG, EEGand/or EMG. In certain embodiments, additional data channels can beincluded to collect additional data, for example, device motion, deviceflex or bed, heart rate and/or ambient electrical or acoustic noise.

The physiological monitors described above and elsewhere in thespecification may further be combined with methods and systems of dataprocessing and transmission that improve the collection of data from themonitor. Further, the methods and systems described below may improvethe performance of the monitors by enabling timely transmission ofclinical information while maintaining the high patient compliance andease-of-use of the monitor described above. For example, the methods andsystems of data processing and transmission described herein thissection of elsewhere in the specification may serve to extend thebattery life of the monitor, improve the accuracy of the monitor, and/orprovide other improvements and advantages as described herein thissection or elsewhere in the specification.

Device Monitoring and Clinical Analysis Platform

The systems and methods described in detail below, may selectivelyextract, transmit, and analyze electrocardiographic signal data andother physiological data from a wearable physiological monitor, such asis described above. The systems and methods described below can improvethe performance of a wearable physiological monitor that simultaneouslyrecords and transmits data through multiple means. For example,selective transmission of extracted data allows for decreased powerconsumption because the wearable patch is not required to transmit allrecorded data. By sending extracted data, much of the analysis may beperformed away from the wearable device without requiring full on-boardrhythm analysis, which can also be highly power consumptive, reducingbattery life. Further, remote analysis without the power constraintsinherent to a wearable device may allow for greater sensitivity andaccuracy in analysis of the data. Decreased power consumption serves toimprove patient compliance because it prolongs the time period betweenor even eliminates the need for device replacement, battery changes orbattery recharging during the monitoring cycle. By decreasing batteryconsumption, longer monitoring times may be enabled without devicereplacement, for example, at least one week, at least two weeks, atleast three weeks, or more than three weeks.

FIG. 18 depicts a general overview of an embodiment of a system 900 forinferring cardiac rhythm information from an R-R interval time series902, as may be generated by a continuous heart rate monitoring device904. The R-R interval time series 902 inputted to the system may includea series of measurements of the timing interval between successiveheartbeats. Typically, each interval represents the time period betweentwo successive R peaks as identified from an ECG signal. R peaks arepart of the QRS complex, a combination of three graphical deflectionstypically seen on an ECG, representing the depolarization of the leftand right ventricles of a mammal's heart. The R peak is generally thetallest and most visible upward deflection on an ECG, and thus makes foran appropriate reference point. However, in further embodiments, anycharacteristic ECG fiducial point (such as the QRS complex onset oroffset) may be used in place of the R peak to provide an estimate of theR-R interval time series. As described above in relation to FIGS. 1through 9 and throughout the specification, the physical characteristicsof the monitoring device are constructed in such a way as to improvesignal fidelity, therefore the high signal fidelity allows for a highlevel of confidence in accurately extracting R-R peak data.

The R-R interval time series 902 data may be extracted from or receivedfrom a dedicated heart rate monitor such as a heart rate chest strap orheart rate watch, or a wearable health or fitness device 906, 908 thatincorporates heart rate sensing functionality. Alternatively, the R-Rinterval time series 902 may be derived from a wearable patch 904designed to measure an ECG signal (for instance, by locating the R peaksin the ECG using a QRS detection algorithm). Furthermore, the R-Rinterval time series 902 may be estimated from an alternativephysiological signal such as that obtained from photoplethysmography(PPG). In this scenario, the peak-to-peak interval time seriesdetermined from the PPG signal may be used as an accurate estimate ofthe R-R interval time series.

In one aspect, a cardiac rhythm inference system 910 is implemented as acloud service or server-based system that exposes an applicationprogramming interface (API) enabling R-R interval time series data orother signal data to be transmitted to the system (for instance, viaHTTP) and the resulting cardiac rhythm information to be returned to thecalling software. The R-R interval time series data 902 or other signaldata may be transmitted to the cloud service directly from theheart-rate monitoring device itself, or indirectly via a smartphone 912,tablet or other internet-enabled communication device 914 that canreceive data from the heart rate monitoring device in either a wirelessor wired manner. In addition, the R-R interval time series data 902 orother signals may be transmitted from a server 916 that stores the datafor a number of users.

In some embodiments, a cardiac rhythm inference system 910 is providedthrough a software library that can be incorporated into a standaloneapplication for installation and use on a smartphone, tablet or personalcomputer. The library may provide identical functionality to that of theinference service, but with R-R interval time series data 902 or othersignal data transmitted directly through a functional call, as opposedto through a web service API.

In certain embodiments, a cardiac rhythm inference system may accept aplurality of R-R interval time series measured from devices of a givenuser 918, in addition to an individual R-R interval time series 902. Inthis scenario, the system computes the frequency and duration of each ofthe cardiac rhythm types inferred from the collection of time seriesdata. These results may then be used to estimate confidence statisticsfor each type of cardiac rhythm based on the frequency and duration ofoccurrence of that rhythm across the various time series. In addition,the rhythm confidence statistics may be updated in a sequential mannerfor each separate call of the inference service. Furthermore, in someembodiments, the cardiac rhythm information inferred by the system maybe provided back to the calling software only in the event that theconfidence score for a given rhythm type exceeds a pre-determinedthreshold value.

In particular embodiments, a cardiac rhythm inference system 910 mayaccept additional sources of data, generally described as alternatesensor channels, in addition to R-R interval time series data, toenhance the accuracy and/or value of the inferred results. Oneadditional source of data includes user activity time series data, suchas that measured by a 3-axis accelerometer concurrently with the R-Rinterval time series measurements. In addition, the system may acceptother relevant metadata that may help to improve the accuracy of therhythm analysis, such as user age, gender, indication for monitoring,pre-existing medical conditions, medication information, medical historyand the like, and also information on the specific day and time rangefor each time series submitted to the system. Furthermore, themeasurement device might also provide some measure of beat detectionconfidence, for example, for each R-Peak or for sequential time periods.This confidence measure would be based on analysis the recorded signalthat, in typical embodiments, would not be recorded due to storage spaceand battery energy requirements. Finally, in the particular case thatthe R-R interval time series data are derived from an ECG signal, thesystem may accept additional signal features computed from the ECG.These features may include a time series of intra-beat intervalmeasurements (such as the QT or PR interval, or QRS duration), or a timeseries of signal statistics such as the mean, median, standard deviationor sum of the ECG signal sample values within a given time period.

The various aspects described above could be used either individually orin combination to provide an application providing insights into anindividual's health, stress, sleep, fitness and/or other qualities.

Some embodiments concern a system for selective transmission ofelectrocardiographic signal data from a wearable medical sensor. Currentwearable sensors, such as the iRhythm ZioPatch™ 904, and furtherdescribed above in relation to FIGS. 1-9, are capable of recording asingle-lead electrocardiogram (ECG) signal for up to two weeks on asingle battery charge. In many situations however, it is desirable forthe sensor to be able to transmit, in real-time or near real-time,specific sections of the recorded ECG signal with clinical relevance toa computer device, such as either a smartphone 912 or aninternet-connected gateway device 914 for subsequent processing andanalysis. In this way, the patient or their physician can be providedwith potentially valuable diagnostic ECG information during the periodthat the patient wears the sensor.

As described above, a significant challenge with this approach is tomanage the battery life of the wearable sensor without requiringreplacement or recharging, both of which reduce user compliance. Eachtransmission of an ECG from the sensor to a smartphone or local gatewaydevice (using, for example, Bluetooth Low Energy) results in asubsequent reduction in the total charge stored in the sensor battery.Some embodiments of the present disclosure, particularly those of FIGS.17 to 24 address this issue through the use of a novel hardware andsoftware combination to enable the selective transmission of clinicallyrelevant sections of ECG from a wearable sensor.

In certain embodiments, the wearable sensor incorporates either asoftware, hardware or hybrid QRS detector that produces a real-timeestimate of each R-peak location in the ECG. The R-peak location data isthen used to compute an R-R interval time series that is subsequentlytransmitted to a smartphone or gateway device according to a predefinedschedule (for example, once per hour). In addition, a time stamp is alsotransmitted which stores the onset time for the R-R interval time seriesrelative to the start of the ECG recording. Since the R-R interval timeseries for a given section of ECG is significantly smaller (in terms ofbytes occupied) than the ECG signal itself, it can be transmitted withconsiderably less impact on battery life.

In some embodiments of a second stage of the system, the R-R intervaltime series together with the onset time stamp is subsequentlytransmitted by the smartphone or gateway device to a server. On theserver, the R-R interval time series is used to infer a list of the mostprobable heart rhythms, together with their onset and offset times,during the period represented by the time series data. The list ofinferred heart rhythms is then filtered according to specific criteria,such that only rhythms matching the given criteria are retained afterfiltering. A measure of confidence may also be used to assist infiltering the events in a manner that might improve the PositivePredictivity of detection.

In certain embodiments of a third stage of the system, for each rhythmin the filtered rhythm set, the server transmits to the smartphone orgateway device the onset and offset time for that specific rhythm. Inthe event that the inferred rhythm duration exceeds a pre-definedmaximum duration, the onset and offset times may be adjusted such thatthe resulting duration is less than the maximum permissible duration.The onset and offset times received by the gateway are then subsequentlytransmitted to the wearable sensor, which in turn transmits the sectionof the recorded ECG signal between the onset and offset times back tothe gateway. This section of ECG is then transmitted to the server whereit can be analyzed and used to provide diagnostic information to thepatient or their physician.

In some embodiments, the system fundamentally allows a device worn forup to about: 14, 21, or 30 days or beyond without battery recharging orreplacement (both activities that reduce patient compliance and,therefore, diagnostic value) to provide timely communication ofasymptomatic arrhythmia events. This development is motivated bytechnology constraints: in order to enable a small, wearable device thatdoes not require battery change or recharging while providing continuousarrhythmia analysis with high accuracy, it is desirable to limit thecomplexity of analysis performed on-board. Similarly, streaming of allof the recorded ECG data to an off-board analysis algorithm may not bepractical without imposing greater power requirements. This motivates amore creative “triage” approach where selected features of the recordedECG signal, including but not limited to R-R intervals, are sent forevery beat, allowing a customized algorithm to locate a number (forexample, 10) of 90-second events to request from the device in fullresolution to support comprehensive analysis, for example, a resolutioncapable of supporting clinical diagnosis.

In some embodiments, the system would provide the ability to detectasymptomatic arrhythmias in a timely manner on a wearable, adhesivelyaffixed device that does not require frequent recharging or replacement.This would be used to enhance the value of some current clinicalofferings, which only provide clinical insight after the recording iscompleted and returned for analysis.

In certain embodiments, the system would allow actionable clinicalinsight to be derived from data collected on low-cost, easy-to-useconsumer wearable devices that are otherwise only focused on fitness andwellness. For example, the technology could be used to create a veryeffective, low-cost screening tool capable of detecting the presence ofAtrial Fibrillation in the at-large population. By using such a tool,not only would patients in need of care be found more easily, but it maybe done earlier and more cost effectively, which lead to betteroutcomes—namely, through reducing stroke risk by identifying AF morequickly.

In particular embodiments, the system may provide the service through adownloadable application that, after receiving customer consent for dataaccess and payment approval, would initiate access and analysis ofheartbeat data stored from wearable devices, either stored locally in amobile device or in an online repository. This data pull and analysiswould happen through an Algorithm API, and would result in a clinicalfinding being sent back to the application to be provided to the user.If the data was sufficient to support a “screening oriented” finding,for example, “Likely presence of an irregular rhythm was detected”, theapplication would direct them to a cardiologist where a morediagnostically focused offering, for example, the ZIO® Service, could beprovided to support clinical diagnosis and treatment. In furtherembodiments, as also described elsewhere in the specification, thesystem may trigger an alarm if a particular measurement and/or analysisindicates that an alarm is needed.

Further examples of additional scenarios of clinical value may includecoupling ambulatory arrhythmia monitoring with a blood-alcohol monitorto study the interaction of AF and lifestyle factors. For example,ambulatory arrhythmia monitoring could be coupled with a blood-glucosemonitor to study the impact of Hypoglycemia on arrhythmias.Alternatively, ambulatory arrhythmia monitoring could be coupled with arespiratory rate and/or volume monitor to study the interaction of sleepapnea and breathing disorders. Further, there could be evaluation of thehigh rates of supraventricular ectopic beats as a potential precursorfor AF (for example, 720 SVEs in 24-hour period).

Extraction, Transmission, and Processing Systems

FIG. 19 is a schematic illustration of an embodiment of a system andmethod 1000 for a wearable medical sensor 1002 with transmissioncapabilities, similar to the system and/or method described above inrelation to FIG. 19. In some embodiments, sensor 1002, which may be anytype of sensor or monitor described herein this section or elsewhere inthe specification, continuously senses an ECG or comparable biologicalsignal 1004 and continuously records an ECG or comparable biologicalsignal 1004. In certain embodiments, the sensing and/or recording stepsmay be performed intermittently. The collected signal 1004 may then becontinuously extracted into one or more features 1006, representingexample features A, B, and C. The features are not intended to besamplings of different temporal sections of the signal, instead (as willbe described in greater detail below) the different features maycorrespond to different types or pieces of data such as R-peak locationsor R-peak amplitudes. The features of the ECG or comparable biologicalsignal are extracted to facilitate analysis of the signal 1004 remotely.In certain embodiments, features are extracted on a windowed basis, withthe window size varying for example between 1 hour or multiple hours toa few seconds. In certain embodiments, the window may be at most: about0.1 second, about 1 second, about 2 seconds, about 3 seconds, about 5seconds, about 10 seconds, about 30 seconds, about 1 minute, about 5minutes, about 30 minutes, about 1 hour, about 2 hours, about 4 hours,or more than 4 hours. The extraction windows may be separated by variousamounts of time if they are repeated. For example, the extractionwindows may be separated by at least: about 30 seconds, about 1 minute,about 5 minutes, about 30 minutes, about 1 hour, about 3 hours, about 6hours, about 12 hours, about 24 hours, about 48 hours, or more thanthree days. In certain embodiments, the windowing sizes may varydepending on the feature extracted. Feature extraction may be limited toone type or various types of features, and features chosen forextraction may vary depending on the nature of the signal observed.

A wide variety of different types of ECG or comparable biological signalfeatures may be extracted. For example, R-peak locations may beextracted. In certain embodiments, the R-peak locations are extractedvia various methods such as: a Pan-Tompkins algorithm (Pan and Tompkins,1985), providing a real-time QRS complex detection algorithm employing aseries of digital filtering steps and adaptive thresholding, or ananalog R-peak detection circuit comprising an R-peak detector consistingof a bandpass filter, a comparator circuit, and dynamic gain adjustmentto locate R-peaks. The RR-intervals may be calculated from peaklocations and used as the primary feature for rhythm discrimination. Inembodiments, an R-peak overflow flag may be extracted. If more than acertain number of R-peaks were detected during a given time window suchthat not all data can be transmitted, a flag may be raised by thefirmware. Such an extraction may be used to eliminate noisy segmentsfrom analysis, on the basis that extremely short intervals of R-R arenot physiologically possible. With similar motivation, an R-peakunderflow flag may be extracted to indicate an unrealistically longinterval between successive R peaks, provided appropriate considerationsfor asystole are made in this evaluation. In an alternativeimplementation with the same goal, the lack of presence of R peaks in aprolonged interval could be associated with a confidence measure, whichwould describe the likelihood that the interval was clinical orartifact.

In general, the word “module,” as used herein, refers to logic embodiedin hardware or firmware, or to a collection of software instructions,possibly having entry and exit points, written in a programminglanguage, such as, for example, Python, Java, Lua, C and/or C++. Asoftware module may be compiled and linked into an executable program,installed in a dynamic link library, or may be written in an interpretedprogramming language such as, for example, BASIC, Perl, or Python. Itwill be appreciated that software modules may be callable from othermodules or from themselves, and/or may be invoked in response todetected events or interrupts. Software modules configured for executionon computing devices may be provided on a computer readable medium, suchas a compact disc, digital video disc, flash drive, or any othertangible medium. Such software code may be stored, partially or fully,on a memory device of the executing computing device, such as thecomputing system 13000, for execution by the computing device. Softwareinstructions may be embedded in firmware, such as an EPROM. It will befurther appreciated that hardware modules may be comprised of connectedlogic units, such as gates and flip-flops, and/or may be comprised ofprogrammable units, such as programmable gate arrays or processors. Theblock diagrams disclosed herein may be implemented as modules. Themodules described herein may be implemented as software modules, but maybe represented in hardware or firmware. Generally, the modules describedherein refer to logical modules that may be combined with other modulesor divided into sub-modules despite their physical organization orstorage.

Each of the processes, methods, and algorithms described in thepreceding sections may be embodied in, and fully or partially automatedby, code modules executed by one or more computer systems or computerprocessors comprising computer hardware. The code modules may be storedon any type of non-transitory computer-readable medium or computerstorage device, such as hard drives, solid state memory, optical disc,and/or the like. The systems and modules may also be transmitted asgenerated data signals (for example, as part of a carrier wave or otheranalog or digital propagated signal) on a variety of computer-readabletransmission mediums, including wireless-based and wired/cable-basedmediums, and may take a variety of forms (for example, as part of asingle or multiplexed analog signal, or as multiple discrete digitalpackets or frames). The processes and algorithms may be implementedpartially or wholly in application-specific circuitry. The results ofthe disclosed processes and process steps may be stored, persistently orotherwise, in any type of non-transitory computer storage such as, forexample, volatile or non-volatile storage.

The various features and processes described above may be usedindependently of one another, or may be combined in various ways. Allpossible combinations and subcombinations are intended to fall withinthe scope of this disclosure. In addition, certain method or processblocks may be omitted in some implementations. The methods and processesdescribed herein are also not limited to any particular sequence, andthe blocks or states relating thereto can be performed in othersequences that are appropriate. For example, described blocks or statesmay be performed in an order other than that specifically disclosed, ormultiple blocks or states may be combined in a single block or state.The example blocks or states may be performed in serial, in parallel, orin some other manner. Blocks or states may be added to or removed fromthe disclosed example embodiments. The example systems and componentsdescribed herein may be configured differently than described. Forexample, elements may be added to, removed from, or rearranged comparedto the disclosed example embodiments.

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while some embodiments do not include, certainfeatures, elements and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements and/or steps areincluded or are to be performed in any particular embodiment. The term“including” means “included but not limited to.” The term “or” means“and/or.”

Any process descriptions, elements, or blocks in the flow or blockdiagrams described herein and/or depicted in the attached figures shouldbe understood as potentially representing modules, segments, or portionsof code which include one or more executable instructions forimplementing specific logical functions or steps in the process.Alternate implementations are included within the scope of theembodiments described herein in which elements or functions may bedeleted, executed out of order from that shown or discussed, includingsubstantially concurrently or in reverse order, depending on thefunctionality involved, as would be understood by those skilled in theart.

All of the methods and processes described above may be at leastpartially embodied in, and partially or fully automated via, softwarecode modules executed by one or more computers. For example, the methodsdescribed herein may be performed by the computing system and/or anyother suitable computing device. The methods may be executed on thecomputing devices in response to execution of software instructions orother executable code read from a tangible computer readable medium. Atangible computer readable medium is a data storage device that canstore data that is readable by a computer system. Examples of computerreadable mediums include read-only memory, random-access memory, othervolatile or non-volatile memory devices, CD-ROMs, magnetic tape, flashdrives, and optical data storage devices.

It should be emphasized that many variations and modifications may bemade to the above-described embodiments, the elements of which are to beunderstood as being among other acceptable examples. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure. The foregoing description details certainembodiments. It will be appreciated, however, that no matter howdetailed the foregoing appears in text, the systems and methods can bepracticed in many ways. For example, a feature of one embodiment may beused with a feature in a different embodiment. As is also stated above,it should be noted that the use of particular terminology whendescribing certain features or aspects of the systems and methods shouldnot be taken to imply that the terminology is being re-defined herein tobe restricted to including any specific characteristics of the featuresor aspects of the systems and methods with which that terminology isassociated.

Various embodiments of a physiological monitoring device, methods, andsystems are disclosed herein. These various embodiments may be usedalone or in combination, and various changes to individual features ofthe embodiments may be altered, without departing from the scope of theinvention. For example, the order of various method steps may in someinstances be changed, and/or one or more optional features may be addedto or eliminated from a described device. Therefore, the description ofthe embodiments provided above should not be interpreted as undulylimiting the scope of the invention as it is set forth in the claims.

Various modifications to the implementations described in thisdisclosure may be made, and the generic principles defined herein may beapplied to other implementations without departing from the spirit orscope of this disclosure. Thus, the scope of the disclosure is notintended to be limited to the implementations shown herein, but are tobe accorded the widest scope consistent with this disclosure, theprinciples and the novel features disclosed herein.

Certain features that are described in this specification in the contextof separate embodiments also can be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment also can be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, such operations need not be performed in the particular ordershown or in sequential order, or that all illustrated operations beperformed, to achieve desirable results. Further, the drawings mayschematically depict one more example processes in the form of a flowdiagram. However, other operations that are not depicted can beincorporated in the example processes that are schematicallyillustrated. For example, one or more additional operations can beperformed before, after, simultaneously, or between any of theillustrated operations. Moreover, the separation of various systemcomponents in the embodiments described above should not be interpretedas requiring such separation in all embodiments. Additionally, someembodiments are within the scope of the following claims. In some cases,the actions recited in the claims can be performed in a different orderand still achieve desirable results.

What is claimed is:
 1. An electronic device for monitoring physiologicalsignals in a user, the device comprising: a housing enclosing a hardwareprocessor, the housing further comprising a rigid shell surrounding aflexible frame and forming a peripheral exterior of at least a portionof the housing, wherein a button is formed within an opening of theflexible frame, the button being configured to be manually depressed bythe user into the flexible frame; and an electrode configured to detectphysiological signals of the user when the electrode is engaged with asurface of the user.
 2. The electronic device of claim 1, furthercomprising a flexible wing extending from the housing.
 3. The electronicdevice of claim 2, further comprising a trace layer coupled to theflexible wing and configured to transmit electrical signals from theelectrode to the hardware processor, the trace layer comprising apolymeric body extending from a first contact region positioned adjacentthe electrode to a second contact region positioned adjacent thehardware processor.
 4. The electronic device of claim 3, wherein thetrace layer comprises a conductive material disposed on a first side ofthe polymeric body, the conductive material having a first conductance,and a resistor disposed on the first side of the polymeric bodyintersecting the conductive material between the first and secondcontact regions, the resistor having a second conductance.
 5. Theelectronic device of claim 4, wherein the first conductance is greaterthan the second conductance such that the resistor applies a resistancebetween the first and second contact regions.
 6. The electronic deviceof claim 4, wherein the trace layer comprises one or more vias extendingthrough the polymeric body of the trace layer and filled with aconductive material, the one or more vias electrically connecting theconductive material disposed on the first side of the polymeric body anda conductive material disposed on a second side of the polymeric bodyopposite the first side.
 7. The electronic device of claim 6, whereinthe vias are positioned at the second contact region.
 8. The electronicdevice of claim 4, wherein the first contact region comprises a holethrough a center of the first contact region to allow moisture totranspire from hydrogel through a flexible wing.
 9. The electronicdevice of claim 4, wherein the first contact region is positioned overthe electrode.
 10. The electronic device of claim 4, wherein the firstcontact region comprises a hole surrounding the electrode such that theelectrode is arranged concentrically inside the hole, the electrodeconfigured to electrically connect to a circumference of the hole. 11.The electronic device of claim 4, wherein the first contact region ispositioned on a bottom side of the trace layer and the second contactregion is positioned on a top side of the trace layer.
 12. An electronicdevice for monitoring physiological signals in a user, the devicecomprising: a housing, the housing comprising: a rigid shell forming aperipheral exterior of at least a portion of the housing, a flexibleframe surrounded at least partially by the rigid shell, and a button isformed within an opening of the flexible frame, the button beingconfigured to be manually depressed by the user into the flexible frame;and an electrode configured to detect physiological signals of the userwhen the electrode is engaged with a surface of the user.
 13. Theelectronic device of claim 12, the device comprising: an adhesive layercoupled to a bottom surface of a flexible wing of the electronic devicefor adhering the electronic device to the user, wherein the flexiblewing and/or the adhesive layer comprises a therapeutic agent fordelivery to the surface of the user, the adhesive layer being configuredto allow the therapeutic agent to the be eluted through the adhesivelayer to the surface of the user.
 14. The electronic device of claim 13,wherein the adhesive layer comprises a hydrocolloid.
 15. The electronicdevice of claim 13, wherein the therapeutic agent is configured toreduce skin irrigation, reduce itchiness, reduce bacterial growth,induce histamine release, and/or provide an anesthetic effect.
 16. Theelectronic device of claim 13, wherein the therapeutic agent isdissolved into the adhesive layer.
 17. The electronic device of claim13, wherein the therapeutic agent is contained within a plurality ofpockets disposed within one or more substrate layers of the flexiblewing.
 18. The electronic device of claim 17, wherein one or moresubstrate layers of the flexible wing comprises pores configured to helptransport the therapeutic agent through the flexible wing.
 19. Theelectronic device of claim 13, wherein the adhesive layer comprises oneor more pores configured to help transport the therapeutic agent throughthe adhesive layer to the surface of the user.
 20. An electronic devicefor monitoring physiological signals in a user, the device comprising: ahousing, the housing comprising: a rigid shell forming a peripheralexterior of at least a portion of the housing, a flexible frame disposedwithin a central opening of the rigid shell, and a button disposed on atop surface of the flexible frame, the button being configured to bemanually depressed by the user into the flexible frame; and a sensorconfigured to detect physiological signals of the user when the sensoris engaged with a surface of the user.
 21. The electronic device ofclaim 20, wherein the flexible frame is overmolded to the rigid shell.22. The electronic device of claim 20, wherein the button is a rigidelement and the flexible frame joins the button to the rigid shell, theflexible frame forming a flexible border around the button such that thebutton is a floating button and pressing the button causes the flexibleframe to flex.
 23. The electronic device of claim 20, wherein: whereinthe housing further comprises: a top housing coupled to a bottomhousing, and a column extending downward from the top housing and a postextending upward from the bottom housing, the post being received in thecolumn or the column being received in the post, wherein the column andpost are press-fit together and configured to resist internal forceswithin the housing that promote separating the top housing from thebottom housing.
 24. The electronic device of claim 20, whereincomprising a spring positioned between a bottom surface of the bottomhousing and a hardware processor of the electronic device, the springconfigured to subsume tolerance stack within the housing.
 25. Theelectronic device of claim 24, wherein the housing encloses a batteryand the spring is further configured to bias traces electricallyconnected to battery terminals and a trace electrically coupled to thesensor into electrical contact with the hardware processor.
 26. Theelectronic device of claim 25, wherein the electrical contact is madevia a plurality of spring contacts.
 27. The electronic device of claim24, wherein the spring is a wave spring.
 28. The electronic device ofclaim 20, wherein comprising a spacer positioned between the hardwareprocessor and a battery, the spacer being configured to maintain thebattery at a constant separation distance from the hardware processor.29. The electronic device of claim 20, wherein comprising foampositioned between a bottom surface of the housing and the hardwareprocessor, the foam configured to subsume tolerance stack within thehousing.
 30. The electronic device of claim 20, wherein the hardwareprocessor comprising a trigger input configured to be manually actuatedby a user for indicating a trigger event, the opening being positionedover the trigger input, and the button being configured to be manuallydepressed to actuate the trigger input.